Ever since I updated to AE 2021 I've been having severe problems with text layers. I'm constantly having to reset the character panel and I'm frequently unable to paste text copied from external documents... which is a huge problem.
Am I just doing something wrong? Is there a setting I should change somewhere? Are there any known issues?
Not being able to paste text from external documents or apps, is a known issue and After Effects team is working on a fix. Workaround: Launch After Effects first and then open the project. The issue only persists if After Effects is launched by double-clicking a project file or by right-clicking a project file and selecting “Open with After Effects”.
As Kyle suggested, a screen recording would be helpful to understand the other issues you're having with the text layers.