Are you using KDE? I'm on a fresh install of Arch with KDE Plasma on my gaming computer and I agree, it's janky as fuck. I've gone through everything I can find about how to deal with the flicker, but it's still there and it's an awful experience.

I have none of these issues on my Arch laptop with Gnome, so I'm going to switch my desktop to Gnome too when I have the time. Plasma is not ready for mainstream use if this is the best that it gets. Gnome however is awesome!

So, I suggest changing your DE to Gnome. If that doesn't fix the problem then switch to Pop!_OS. It's a completely plug and play distro and I never had a single problem with it. I only switched to Arch because I wanted to get HDR support which requires Plasma. Well, it's not worth it. I can't even use adaptive sync which is a pretty big deal for gaming.

Good luck, we're all counting on you.

Edit: otherwise Arch is an awesome distro. The power you have with all of the available programs is great! So, now it's just about getting the screen rendering to be stable.