Slow Shutdown Time

Hi there, just bought my very first Apple computer, a maxed out m1 imac 24. For the first two weeks, while I was the sole user, the shutdown time was very fast. We're talking 5 seconds, maybe. However, the moment I've created another user for my wife, I noticed that the shutdown time has drastically increased to nearly 40 seconds.. I have plenty of free disk space, and I almost always quit all the apps before shutting the computer down. Thankfully, it doesn't seem to affect the boot up time, or the general performance, which is still just as fast as in the beginning. Has anyone experienced something similar and knows what to do? Can it be just a coincidence that the problem has started when I created that second user? What can be the issue?

Thanks in advance for any help!