I had the same issue, I tried changing my Microsoft Edge's graphics backend (by going to edge://flags and searching up "D3") and changing it to D3D9 instead of Default. This typically happens when I have a video player in the background and a borderless fullscreen app in the background, or if I have discord in the background. Among the fixes I tried, some may work for you:
1. Turning off Game Mode in Settings > Gaming.
2. Changing Edge Webview graphics backend via the Edge app to D3D9 or D3D11.
3. Turning off graphics acceleration in edge settings and in the Discord desktop app (if installed) will likely fix the issue, but it will make some sites, especially those that require 2d or 3d rendering via chromium, a bit laggy.
4. Using a non-Chromium-based browser will likely fix the issue, but no guarantees as this seems to be an edge webview issue of some sorts and has been going on for many users for MONTHS.
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TL,DR; I went ahead to install Windows 11 from scratch and create an account without logging into Microsoft, then only used Firefox for web browsing. Firefox still has a similar issue of loading pages under GPU stress, but it actually shows a short loading screen before fully loading the page instead of bugging out and showing visual artifacts. Steps to accomplish this during installation setup, if you want to attempt a fresh install, which by all means is a last resort past Firefox and the other fixes:
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(WARNING: Before attempting these steps, be sure to have an ethernet cable ready or a way to install Wi-Fi drivers if your motherboard doesn't supply them, otherwise you won't be able to connect to the internet. Alternatively, use a USB Wi-Fi adapter)
1. Disconnect any ethernet cables, as the next step won't work if you connect to the internet.
2. When Windows asks you for language/locality, press Shift+F10 and click the terminal window that pops up.
3. Type in "oobe\bypassnro" to bypass the online registration requirement.
4. Continue installing as normal until it asks for a wifi connection, then press "I don't have internet."
5. Create your offline, local user account via the steps it provides.
6. Once Windows is installed and you're logged in, connect to the internet via ethernet or install Wi-Fi drivers manually.
7. Download Firefox from Edge. If you use Edge for Microsoft Rewards, you can alternatively use Bing as your search engine to still get those rewards, just at a slightly slower pace.
I hope at least one of these fixes your issue, if it doesn't, let me know, and I can try to look into this further. I haven't had this issue in weeks after going microsoft-accountless. It's okay to login to microsoft via the Firefox browser though, that hasn't caused me any issues so far. Just don't connect to Xbox or if you have to, do it via the browser.
