Is it worth making fanfics anymore? Fanmusic? AMVs? Custom sprites?
Therein lies your answer.
Now, whether do you want to make a ROMhack or not that's just a personal matter.
If your problem is that your game might get C&D'd and disappear once it's done, the solution is simple: just like with any worthwhile software project (as that is what it boils down in the end), release the original (as in fancreated) development files to the public, or at least with some sort of license that allows for its distribution and reutilization. (Oh, and avoid giving it too much publicity when you do, like the thing with the professional trailer; a stick figures trailer will probably do, at least in the beginning) In the rare (rare) case that your game gets C&D'd, someone in the community might pick the pieces up. If you want your work to persist past you, be it a fan work or an "established IP" it is your responsibility as a creator to distribute it and liberate it accordingly.
If your problem is that you don't make money off it, unfortunately that's systemic issue with western (at least) cultures treatment of inspiration and remixing of culture having regressed to barbaric levels, so the best thing to do if you really insist on earning money from it is to... well, not earning money from it. Like, I presume the ROMhack would not be the only thing you'd do with your life? So if you have a "personal" / "life" patreon set up, just receive donations for the things you do in general (or just receive donations for anything period) instead of "pay my ROMhack". But remember you are still taking up a fight.
But no matter what, down the line it comes down to if you want to commit to it or not. Making a work, fan or not, comes with a cost and a responsibility.
