I do use grammarly in conjunction to avoid doing any silly mistake.
For the novel I'm currently publishing I just use docs and Google spreadsheets. This last one to tracks the different stats and their progression.
However, I'm writing a much more complex novel, with quite a few connections and turns. For that, I also use draw.io
It is really useful to draw flow charts, which I lay horizontally and use as a timeline. I can pinpoint when a skill will be learnt, where the MC will meet an important character, etc. Plus it makes it easy to keep track of everything, a simple zoom out and I see all the important pieces highlighted in a stronger border width and color.
I create a spreadsheet file for each project with tabs for various notes - character list, places, chapters, timeline, whatever I need for that one - so it's all in one place and easy to find.
I'm obsessive about making backups on both thumb drives and cloud storage, because I've previously lost data both ways.
Old system, which I often miss, was to use pen and paper and then the typed version became a second draft. Because I never throw away anything I've written, that actually turned into an issue as far as storage space. Also, it was a royal nuisance if I realized that I should have done something very different 30 pages back that changes everything from there on. It did, however, draw a clear line: when writing longhand, I could just let the story flow. Once I was at the computer, it was time to get serious.