Overlord's main issues are that it's unpleasant and boring.
There are no stakes because we know Ainz and his minions are insanely OP and are going to win every fight. Everything almost always goes according to plan, and if it doesn't it goes even better than expected for our villain protagonist.
Speaking of our villain protagonist, let's talk about the characters. Most of the Nazarick crew are entirely flat and static when it comes to character development, especially when it comes the past 2 seasons. Ainz somehow does whatever the opposite of character development is, having less and less of a personality over time.
After how decent the first 2 seasons were, I really wanted to believe that this story was going somewhere interesting, but, at least so far, Overlord has been yet another generic power fantasy.
If you find the idea of an infinitely powerful skeleton slaughtering thousands of innocent people for dozens of episodes to be appealing, then you'd probably enjoy this. If you're looking for any kind of depth or substance, I'd recommend watching pretty much anything else.