When I was talking about “battery charging”, I meant using an app to limit the charging at a certain level: look for “acca” or simple “acc” which is the module/daemon to manage that. You have to be root to do that and there is no way around. For the rest, sure, but that’s for GrapheneOS, I was talking in general, most ROM not having what GrapheneOS has and considering GrapheneOS is exclusively present on Pixel phones unfortunately…

Root can be useful for plenty of reasons: there are many apps which use root access to increase privacy, customize the system, restrict apps, manage battery charging, enforce firewall for apps and system, block trackers, backup the system, etc… I currently have 8 apps (if I don’t count all the lsposed modules) using the root privileges to do all of that but I also use it for other things like automation.

The only kind of security I want to have is privacy from my own apps installed on my system, something root privilege allow me to have. For the rest, I just don’t install any random program on my phone and I didn’t have any problem for years.

(and no, I can’t do any of that with shizuku or adb)

(sorry for the late reply) Custom ROMs are something else and are in no way necessary for rooting the phone. You can totally root your phone with Magisk while staying on your manufacturer’s ROM, or flash (install) a custom ROM without rooting the phone and not being locked from anything your Android phone can already do. But you won’t have full access to your phone if you don’t root and will eventually need at least some degree of power over it, which is why most people root their phone too. But custom ROMs alone are also great, you can check if there are good ones (or if there are any) on xda-developers by searching your phone on it. But be careful and follow the instruction to the letter: you won’t be able to blame anybody for bricking your phone (look for hard brick and soft brick) as all authors clearly state they’re in no way responsible if you fuck up something and your phone doesn’t work anymore. The best thing to do as a beginner is to search deeply on the internet for days if not weeks in order to feel more confident and more importantly understand what is a ROM, what is a recovery (TWRP being the main one), a bootloader, etc, so you know what you’re going to do.

Of course they work. Though if you’re rooted, you just need to install/flash a module named “Magiskhide” which will basically hide the apps your want from your root, as a lot of banking apps consider a rooted device not secure enough… (even if it completely is but whatever)