Trump is not going to have a legacy. I think once he's out of power, or maybe after he dies (or both), both the Dems and the GOP will erase him. Sure, he'll be remembered for a disastrous war in Iran that had no point, or his failings dealing with COVID, or the whole January 6th insurrection. But a positive legacy probably sailed away back in August of 2017 when he said there were good people on both sides....
GOPers who supported him will pretend they never did. They will suddenly have backbones and vote to take his name off everything. His legacy is going to be him crashing the US economy not once, but twice, and maybe even Epstein.
And, finally, this Iranian adventure reminds me a lot of the UK and the Suez crisis from the 1950s. They basically had to back the fuck out of that mess and were massively embarrassed. And, not only that, it results in their military power being seriously curbed. As many have said, Everything Trump Touches Dies, and the US is just the latest and biggest thing.