If you want to be with a chubby/fat woman, it's way easier to just go for one that already is. Ik skinny girls to fat girls are hot, but 9 times out of 10 she ain't gonna be into it.
About the self-conscious thing, most fat girls are already self-conscious about it and isn't likely into feederism. You have to be lucky af to find someone who actually is, or is willing to try it. Again, it's more likely they have some sort of mental/eating disorder. Pretty sure you don't want to be with those FA tiktokers who act like they have no brain. And also most of then this day in age are rainbow so the chances are even lowered.
This fetish is mostly a fantasy, not a reality. Most fetishes that has something to do with body parts are of course the usual boobs and ass, feet, and armpits. Even if guys like bellies (at least a little), most girls aren't and will try to cover it (long shirts or high-rised pants), even if it's the tiniest bit of flab. You're not going to see 400 pound blobs in your day to day life. You ain't going to be with anyone who wants a giant belly. You ain't going to be with someone who is reaching immobility. It's all in your head and remains a fantasy.
Realistically the only possible way to have a healthy relationship with a chubby/fat girl to fulfill your sexual desires is to actually put the fetish aside and actually love them for who they are. Most women are submissive and will be willing to fulfill whatever you want if you actually love then for who they are as a person, and not as an object. That's the problem with some of you incels; thinking it's impossible to find someone of your exact type because you just want to have your personal sex doll. You can't really change what you like (in terms of preferences), but if you really want to alter that, actually try to be with women who are in the norm.
Tldr: Most women will not be into feederism and if you want to be with a feedee, stop looking at potential sex dolls and instead as actual people.