i really had a problem naming the subject for this guide/example
what i want to do here is show how to make stuff that is usually boring and dry in litrpg more interesting, while also showcasing my ideas i am enthusiastic about.
i will start with a bad example and then proceed to show a very long good example

bad example: the MC has a cheat that give him 2 classes instead of one like every body else. he got arch-bishop that specialize in strategic magic, and crusader, who specialize in close combat and self buffs.

this was really boring, not because the classes are boring but because they were not presented well. now lets move to a good example and see how the exact same thing can be more interesting, by giving it more depth. we will start with actually explaining, the litrpg part of how blessings of gods work. and then each of the 2 classes, and then the consequences of the cheat:

faith points - earned by praying to the chosen god, and doing religious things like sacrificing, killing in combat (war gods, death gods, ect.). (please note that this is in addition to the regular litrpg system and not a rmplacement) there are 2 stats, max faith (MF), and current faith (CF). when earning faith, it increase current faith until maxed, then it increase max faith together with current faith (example, to go from 6/6 to 7/7, you need 2 points). CF earning when in the process of earning MF, receive also any training bonus that increas MF.

current faith is spent in the following ways:
-buying blessings - spells that work on favor (priest version of mana)
-praying for aid - exactly what it sounds
-wish for boon - basically an item store

a few more key parts of the faith system:
- what available to buy (boon/blessing) is determined by max faith (X item cost 20 CF but need 70 MF to even be able to buy)
-everyone can take part in the fate system, but ALL religious classes have a base in it that is much stronger - much higher increase to MF and CF, and a lot more favor, and huge base favor Regen (more like a huge debuff to all non-religious classes), it is mostly used for praying for aid buy non-religious classes
-a stats buff (str, wis, ect...) for base status that is based on max faith. (i generalize to all base stats to not make this even more complicated)

the crusader:
the crusader is a class that specialize in close combat and getting buffed. they are the front line of any temple. lets look at what makes them OP(every class is OP in its own way). first, they get accesses to a lot of the warrior classes abilities, but they lack the key synergies that supercharge the warriors abilities, but they do get most of the ones that give them options on the field. (like a F-1 formula with an engine of a scooter)
-the bonus to base stats from MF is increased significantly, making the crusader much more powerful and can compensate a somewhat on its own for the lack of supercharging like the warriors
-the warrior skills now also scale with MF, and blessings skill with base stats (or even more if they already scale)
-blessings cast on them are more powerful. this is why they are best at large battles where the back line OP bishops can mega buff them.
and here come what make them OP: they usually get a stat buff blessing for themselves - so the blessing that getting buffed from their added status scaling, MF stats buffed by crusader class, received bless buff, is now very powerful and is adding even more stats, to charge the warrior skills even more. this is important to them since they having a hard time accumulating MF (if they do, they would be totally broken)
-they get a very nice bonus to rising CF since they are constantly on the front line for their god and need stuff early, but they pay for it with lower MF scaling.
-they get a discount for pray for aid.
-extra favor Regen, since the class is meant for the battlefield and constantly casting week blessings
-they get to Regen a percentage of their missing favor when fighting in a fight their god would approve/for their god/close combat, and even more if all 3 at the same time

the arch-bishop:
a class borne to be nurtured and hidden away until the times for it to emerge comes. this class is meant solely for casting the larges, grandest , and expensive battlefield spells that exists, such as the resurrection zone - a dozen of kilometer wide zone that any ally that die in it immediately resurrect, again and again and again.
- huge increase in raising MF, to allow them to unlock high tier spells ASAP
- HUGE increase in max vigor in order to cast said high tier spells
- blessing discount to be able to buy this many expensive high tier battlefield spells
- pray for boon discount - instead of battlefield spells, legendary divine artifacts can sometimes be worth ruining an arch-bishop build for, especially for the larger temples that have many arch bishops already. there is actually another class that specialize in creating holy artifacts, but he goes for quantity instead of truly to top level stuff.
- he can tax allies for part of the favor needed to cast spells
-he can restore a percent of favor when preforming long ceremonies - this lets him a way to regen the huge amount of favor needed for  battle
-allies in that ceremonies get a bonus to max favor that scale with the amount of favor the archbishop gained
-the allies participating in any praying ceremony will benefit from increased rate of faith gained from that ceremony
-the bishop will also get from bonus to faith raising according to how many participated in the ceremony

as you can see, each of the 2 classes is OP in his own way for what he meant to do, and have synergies in itself, that the you might not understand the first time you read, unless they are actually explained, specifically. please read again before proceeding, if you have not grasped all the internal synergies in each class

and now for the cheat class of the Main protagonist (MC):
as was told at the beginning the cheat is simple. having the 2 classes together, on an MC that just want to go adventuring with a small party. lets see what OPness we can see:
-the massive buff to raising MF let the crusader part be even stronger, the buff to blessings from high MF , the buff to warrior skills form high stats and even more powerful blessings. this will also let the MC take even less small blessings and focus even more on raising MF to scale and get to the good stuff.
-this will let the MC save up until he get to a mid-rank stats bless that increase percentage instead of flat (because he has already very high stats)
- his huge max favor let him spend a lot of favor in battle, and the restore percent of missing favor will restore huge amount of favor when low
-he can use his party as favor batteries when he is low, and also make them better over time at this, because of the arch bishop ceremonies
-and most importantly, he can spend CF and restore it quickly to keep raising his MF
-once he reach late tear he is basically a demi god that have the most powerful blessings and status super charged by the synergies, are supercharging the warrior skills, and compensating for warrior weakness, will also casting offensive magic when necessary and unique buffs the warrior want, while wielding powerful artifacts he got as boons.(problem with artifacts is that they are hard to find, even if you are powerful)
-probably many more that can be written but i am tired

this is the kind of stuff i actually want to read and be in stories, i hope you had fun reading, and learned something from this
if you remember any stories that this style reminds you, i will appreciate if you update me

ps,  i am not native English speaker, and i am to tired to find all the spelling mistake i missed, hope you understand