flickering guide lines
In Illustrator 25.4.1 one cannot use the guides while Astute Plugins active! What did you do Adobe? While selecting objects the guide lines will appear blink think suddenly while someone click drags the mouse as long as one releases the mouse button again. While dragging objects, the guide lines will be fine, but with nothing selected, click drag will cause flickering guide lines.
VIDEO on youtube: https://youtu.be/r_GMXaUSH5w
Does switching between GPU and CPU change anything?
Have you tried to reset preferences, as AG advise in their article (https://astutegraphics.com/support/tutorials-and-troubleshooting/resetting-illustrator-preferences)?
You mean that it starts to work fine when you remove AG plugins from the Plugins folder? How do you know that AG plugins cause this?