Hi, I did a quick search for it and i see what you mean. Most of those site assume you already have bootloader unlocked and TWRP installed, but don’t even give good instructions anyway. Here’s a link i found that gives a detailed procedure from beginning to end. It’s from 2022 but it should work. I have done this on an old phone (galaxy A20). Make sure you backup your data. thecustomdroid.com/galaxy-tab-a7-2020-rooting-gui…For degoogling, i would recommend looking up MicroG to replace Gplay store. Good luck!