Isekai is a setup. In many series, there is nothing isekai about it after the first few chapters. In a series like New Life +, it would only be a trivial difference if you called it "Amnesiac blessed by God" instead of an isekai.
As such, I don't believe it's possible to get tired of isekai... I think people who say they are tired of isekai are actually tired of the type of story that is most common among isekai: fantasy worlds with RPG elements. There are lots of series that are fantasy worlds with RPG elements (even with floating menus!) that aren't isekais, though.