If the X-men had a wit of sense their wealthier members would just bribe I mean lobby Congress for pro mutant laws.
A pro-mutant super-PAC funded by Xavier's estate, Emma, Sean, Warren, Monet, Roberto, Betsy, etc. would be pretty cool. Pick a personable non-mutant as the 'face' of the PAC (Sam Guthrie's mom, Lucinda?) and let her run it. International support could come from Atlantis and Wakanda, among other places.
In the earliest years, Xavier had government ties and contacts, but that age of cooperation between the government and mutants seems to be long past. (And some of that might be on Xavier, for not arranging for his students to be better tied into that, so that if he died, it wouldn't all just dry up and blow away.)
Jason Aaron gave them a Krakoa that can shit diamonds because he could not find another way to finance his Wolverine and the X-Men, I do not think they have money problems.