I believe people who claim he will "end democracy" do not believe he will literally put an end to elections. Many places widely considered "undemocratic" also have elections.
> They definitely won't be allowed to vote for him since he'll be at up against the term limit.
I'm sure if Trump were younger and up against term limits, he (and his party) would simply ignore them or change the rules. That's the kind of democracy-ending actions that could easily happen. Lucky for us, I think he's too old for this particular problem.
Trump is not the end he is the means to an end. His party will absolutely change the rules just to take advantage of them in the future.