Thanks, yeah I've seen those instructions before. My only concern is having to do software updates manually but I guess that's not too much of a problem. These instructions look pretty solid for doing that.Actually I am using a G9708 with Android Q (One UI 2.0), it is a carrier specific model of G9700. I still don't have TWRP, but have already rooted my phone using magisk. Here are some instructions I followed, hope that helps.
https://www.youtube.com/watch?v=o3a8YnWT3yk
https://topjohnwu.github.io/Magisk/install.html#samsung-system-as-root