iMac all of a sudden incredibly slow

Hi. I'm having some problems with my iMac. I don't know too much about computers, so I would like some help troubleshooting. I have an iMac 2017 that I use daily for music production and recording. A couple of weeks ago I started having some problems. Clicking pretty much anything results in a spinning wheel and a few minutes of waiting. Starting an app takes several minutes and begins with it telling me it's not responding. I use Logic Pro and it has a very difficult time playing my projects. Pressing play usually results in the project playing for a few seconds, then lagging, glitching, distorting and then stopping, showing me an error message. ''System Overload'' or ''Disk is too slow (Prepare)'' or something similar. Sometimes it can play through the project, but without any sound. I use an external audio interface and audio monitors and I thought that those might be part of the issue. But the problems remain even after disconnecting and turning them off.

I'm running macOS Monterey 12.6.3. I have lots of space left on my hard drive.

The strangest part, to me, is that there have been times where there are no problems whatsoever. Everything runs perfectly, like it should, for a few minutes or an hour, before the problems return. But most of the time, it's running incredibly slow. I have had this exact problem before, maybe a year ago, with the same computer. Then, I stopped using my computer completely, and after a few weeks everything was back to normal.

As you can imagine, it's quite frustrating. Please help, thanks! :)