Sudden and Extreme Lag

Hi, I recently bought a 2019 iMac (with the intel i5 processor, 24 GB of memory). I've ran photoshop CC on my much older and less powerful 2015 macbook air, with no issues. However, since I've started using this computer as my main machine, I've had a ton of lag. I wasn't sure if this was an issue that other people have been having, or if this is something wrong with my computer specifically. I'm not working on particularly large files by any means (8.5 by 11" @300 dpi), with 1-2 layers. When I go to save any file, it tells me that it can't save [file name] due to a program error and it won't work until I hide all my layers. It's borderline unusable. I can't think of any reason why this might be happening, unless PS hasn't been optimized for macOS Big Sur yet? I just can't envision it causing this many problems. Any advice would be appreciated. Thank you!