VirtualXposed VS LSPatch

To add to this, if you want to actually isolate an app, use twoyi or VirtualXPosed. The android work profile is not enough, as lots of data is still shared between the work profile and the normal profile.

(FOSS)VirtualXPosed

I recommend VMOS Pro (Reliable but proprietary with a good privacy policy), or VirtualXPosed (unreliable but FOSS).

link: https://github.com/android-hacker/VirtualXposed

You have to drag and drop the ARM translation kit and use V 0.18.2 of VirtualXposed.

The idea is to try setting up certificate and proxy normally, then install VirtualXposed (you can grab apk from releases), open it, install Japanese version of FFRK inside of VirtualXposed, and at last run the game and see if you can read game traffic. If it works, it could be investigated further if/how this approach could be extended to Global version too. If not - well, it was worth a try.

Once Shizuku Service is running download and install LSPatch (https://github.com/LSPosed/LSPatch/releases/download/v0.5.1/manager.apk)

Then there's the fact that starting with Android 11 it's no longer necessary to first use ADB over USB to initiate ADB over network so, anybody can start ADB on the device itself, use apps like Shizuku, LSPatch (rootless Xposed), LADB, Termux (apt install adb) etc, automate the ADB commands (via Tasker, let's say) on system boot-up and so on (to let's say, disable the shitty OEM/carrier app packages etc).

Taichi is not open-source, even if it might be ok I strongly discourage using it as much as you can. There is an open-soucre equivalent which is LSPatch

LSPatch - A non-root Xposed framework extending from LSPosed

For ADB there's https://anl.ink that provides a nice GUI on Windows. If you'll be using ADB you might also want to checkout LADB, Shizuku & LSPatch.

Download and install latest manager.apk for LSPatch.

Unfortunately, I haven't used Lspatch as I'm always rooted. Didn't find any solid guide online. You can check their github Readme https://github.com/LSPosed/LSPatch/blob/master/README.md

You also have the option to add Magisk or some other root method of your choosing - yes, despite I have my gripes with the way Google is "sanitizing & normalizing" Magisk at the expense of harassing certain individuals via trolls in the community to discourage them from making their own builds of it and sharing them I guess it's still overall positive that such stuff are becoming more accessible over the years like this.

For AdBlock, if you're on Android 9+, you can do to Wifi Settings, then Private DNS, and set dns.adguard.com as the custom DNS. For Xposed, you can look into LSPatch. I never used it before tho so I can't really help you with how it works.