I've watched both SAO and Re:Zero. Well, I really enjoyed Re:Zero due to many things but the main takeaway was that the main character was a weak one rather than a Strong one and also, he undergone different hardships rather than the enjoyment that most Isekai's MCs undergo. It was one of my best Isekai.
For Overlord, I think I'll wait this out and not try it based on your description.
Is it different from a regular Isekai plot?
In Overlord the MC is an overpowered character. I'd describe him as a lawful evil character like in Dungeons and Dragons. He does evil stuff but his intentions are not necessarily evil.
That's a nice plot, I'll look into it, thanks.