Intel HD 500 glitches with X11

After installing Ubuntu 20.04.2 on a NUC 8CCHKR¹ the system works mostly as expected, however resizing windows results in a temporary jumbled mess². If you get it pixel-perfect (new positions every time) it can also stay for a couple seconds.

I couldn't make screenshots, and recording with simplescreenrecorder didn't work, either - during recording it just slowed down to 5-10 fps, but displayed everything correctly, but the preview window did catch it while not recording.

Scaling an application like Firefox is similarly slow, and with that the glitches are much rarer and disappear almost immediately.

Likely related, freerdp2, both x11 and Wayland versions are much slower at hardware-accelerated rendering than Remmina with its software rendering, about as slow as when I tried recording.

OpenGL seems unaffected. Seemingly no correlation to resolution/framerate. BIOS version doesn't affect this.

System logs³ don't give anything suspicious, actually they have the least amount of regular warnings I've ever seen.

If necessary, I could try to capture the HDMI output

Is this something that can be fixed?

¹ https://www.intel.com/content/www/us/en/products/boards-kits/nuc/kits/nuc8cchkr.html
CPU: Intel Celeron N3550 2C2T @1.10GHz
GPU: Intel HD 500
RAM: 3.2 GiB (3391980 KiB)
Motherboard: K44798-506 / NUC8CCHB

² https://gitlab.com/MrHeating/logsnstuff/-/raw/master/VID_20210225_104424a.mp4?inline=false

³ https://gitlab.com/MrHeating/logsnstuff/-/raw/master/NUC8CCHKR_logs?inline=false