FEMA didn't exist for the first 200 years of the United States. If it has always been a core function of government (after more core functions like border protection and a fair, non-weaponized justice system), then it was handled by the States for longer than by the Federal government.
I'm not saying FEMA is unconstitutional; only that FEMA is allowed rather than required at the national level, and there could be other ways to handle the function. FEMA was politically weaponized after Hurricane Milton. That is banana republic type behavior, and organizations in which that happens should have their houses cleaned, with layoffs, so future employees know they should not do that, and will act professionally instead.