It sounds like a pitch for a Hollywood project: A pair of movie stars find themselves as the new owners of a famous old football club from a downtrodden part of Wales, discovering that all their money and celebrity friends mean nothing to the diehard fans of the club, who are skeptical of their new benefactors. But rather than a heartwarming sports comedy that teaches the characters and the audience something about finding a family where you least expect it (or some other rote cliché), that is actually the premise for “Welcome to Wrexham” — a documentary series made by FX and showing on Disney+. Rob McElhenney and Ryan Reynolds really did buy Wrexham AFC and really did find themselves in the crosshairs of suspicious fans who could not decide if the two stars were the club’s guardian angels or simply fame-hungry narcissists with an eye on strip-mining their beloved team. As part of their attempt to win over the fans, the pair are using “Welcome to Wrexham” as a way to document the first two years of their tenure and to give fans and viewers a window into the reasons behind the ostensibly baffling business decision to purchase a struggling football club. Because let’s be very clear: This is not a sports series in the vein of Amazon’s “All or Nothing” show, which followed teams such as Manchester City, Juventus and Arsenal. “Welcome to Wrexham” is a very different proposition. Much like the club’s owners, there is a playfulness and silliness that pervades the show. For every hard-talking business meeting, there is a segment on the pair making Welsh cakes. And for every heart-wrenching drama on the pitch, there is a mood-lifting look at the juxtaposition of two global megastars and a small Welsh football team. But, bafflingly, it works. Sure, it is a little contrived at times, and McElhenney and Reynolds occasionally come across as achingly desperate to be liked. But the series does give you a very honest-feeling look at why and how these two movie stars decided to take on such a left-field challenge. Over the course of two years, Wrexham fans began to believe that their new owners were serious about lifting their team through the leagues. By the end of “Welcome to Wrexham,” viewers will be too.