Anyone have trouble with their Beelink?

I got this Beelink mini pc from Amazon planning to hook it up to my living room TV and play movies and stream TV with. And I was shocked and amazed to discover that this little thing could run games like Hi-Fi Rush and MGSV:PP on max settings! Sure the fans made it sound like a small jet engine, but it never skipped frames or lagged on me even once! I know it's not a power house: it couldn't run Yakuza Zero or Neir Automata very well. But I was still thrilled with what it could do!

Well it shipped with Windows 11, and I finally decided to fix that. A couple days ago I switched over to Mint, tho I'm running Kubuntu now. The switch was quick and painless, and honestly getting used to Linux has been pretty fun! But now it runs a lot of my games like a slide show. I've been digging at this for a few days now, updating drivers and setting up Proton. I've found a lot of helpful guides and stuff on line, but very little about the hardware I have in this situation. Apparently AMD processors are great for Linux, but I feel like it's not working with the integrated graphics card. Tried to find the right driver on their website, but I haven't had much luck. So, here's hoping the community can help. Any tips for a newbie?

CPU: AMD Ryzen 7 5700U (16) @ 4.37 GHz | GPU: AMD Lucienne [Integrated]

UPDATES:

Thanks again to everyone so far that's offered advice, but it hasn't seemed to have helped much..

I made sure the power mode is set to Performance, and turned the settings all the way to their lowest at 1080p. Someone had suggested using Flatseal to check permissions, but steam did not show up there, so it was seemingly a dead end. I even switched to Bazzite.

But I'm still only getting 10fps at most, regardless of graphic settings. I'm not really sure what else to do at this point.