Thanks for replying!
You have a very responsive community here 
I have already reinstalled KDE #LOL. I tried tinkering on my own and messed up even more xD.
I am new to Arch Linux and new to Linux in general, but I love it. Garuda KDE is so snappy and customisable! I tried many distros but they are just not performant as this one! 
I like this philosophy Unused RAM is wasted RAM.
I was trying to see if open source driver could keep my Nvidia under 44-45 C degrees as it makes noise. On windows it used to stay pretty much all the time at 38-39 degrees. I don't play video games anymore.. but I don't have an integrated GPU.
I amalso on youtube trying to learn more Linux commands.
So my BTRFS Assistant issue has been resolved.
At the moment I am trying to understand the kernel thing - was reading this forum post.
I have, installed by default, linux-zen 5.16.8 zen1-1 but I also installed linux-lts 5.15.22-246
Since I am not gaming, which one should I use? And how can I change between kernels at start?
Garuda boot options doesn't want to keep my LTS as main. What do you think?