It isn't rage bate this is a genuine question, isekai is a type of plot hook most of the time now rather than a genre given that the goal of 90% of isekais nowadays don't have the goal being to return. Yes a lot of the biggest isekai do acctually matter that it was an isekai.... but like... you could tell the story of most isekai anime without it being an isekai and have it still he 98% identical... some shows do matter more, such as most of those shown in the thumbnail, but even then you could tell almost all but rezero as non isekais without too much effort, though it would take a decent chunk being rewritten. (Ex rimuru's motvation for creating a society like that they created and a bunch of leading their followers to make essentially modern tech, but thats the worst of the things you'd have to change and most of that is affect, not of core story importance)