You get three kinds of adult converts. The first kind of convert wants to marry somebody Catholic. They're joining because they love somebody. The second kind of convert was approached by missionaries that built their community a school or a well or something, and they're grateful that somebody clearly cares about them and their community.
The third type of convert, though, joins because they like the structure. They like the gravitas. They like the moral absolutes. They like the patriarchal hierarchy that doesn't let women lead. They sign up and immediately declare that Vatican 2 was a terrible mistake and that all of the popes since then have been illegitimate. JD Vance didn't join because he loved their soup kitchens.
The third group ends up joining the Russian Orthodox church.