the biggest problem with a league corruption plot (although it would be a lovely parallel to actual FIFA), is that it's not a very 'tangible' story. what i mean by that is that it lacks that sort of momentum needed in a kids'/younger people's story. might make an interesting TV drama or book, but for a kids video game that plotline lacks the meat needed.
well, i think the site does explicitly say that they like Marnie because they think she's pretty and talented. and i think the important thing to note is that Team Yell is quite literally fans (stans?). so if football is to gym battles, then clubs are to the trainers themselves. so they want her to be the champion of Galar because go Real Madrid.The first instance I bolded is important: why do they want Marnie specifically to become Galar's champion, let alone get passionate enough to do what they do for her in the first place? They don't really seem evil at all if the caption about Marnie being able to get them to stop certain instances of trouble-making is any indication.
Again, this makes me question why they do these things in the first place and what they see in her.
so as a starting point i think it's pretty important to note that both Bede and Marnie are stated to have ~ secret ~ plans. Bede clearly seems to be shaping up to be a major, if not the primary, antagonist of the game. Marnie seems like she's slated to play a Lillie-esque role in the story. so it would seem almost that her story is going to be explicitly stopping Bede or impeding (whether by actual knowledge of Bede's plans or knowing that someone could eventually cause a problem) someone like Bede from doing bad.Now, let's turn our attention to Marnie's description.
Now, what exactly is this goal of Marnie's anyways? It could be about charity donations or something not really related to the plot, but I find it more likely that this goal of hers is the very reason why Team Yell backs her up in the first place. Given how they're well-intentioned and the fact that Marnie doesn't seem malicious, I think it's possible that Marnie and Team Yell caught on to the Pokémon League's corruption, leading to Marnie having a secretive reason for becoming champion while also explaining why Team Yell is going to such extremes to keep Marnie on top (as she's the only person they trust to reform the Galar Pokémon League).
the other big problem i would say with a "League reform" story is that becoming champion seemingly wouldn't resolve it. you know, tracing back to the analogy, with the League being FIFA, there doesn't seem like there'd be much she would be empowered to do as champion.
the execution can matter though. i mean, Team Rocket through Flare were literally all the same song and dance, but they're still a degree distinct simply because of the personalities involved, their goals, and what they end up doing. Team Yell seems truly benign; Team Skull was written to be aimless and comical simply because they were there to eventually be a ~ twist ~ and reveal the real antagonist as Lusamine.Not only would this avoid having Team Yell being a complete retread of Team Skull (being hired by someone to make Marnie look bad is too much like how Lusamine used Team Skull), but this would technically give us a genuine vigilante team! Team Plasma came close to this, but they were manipulated by the Seven Sages (mainly Ghetsis) from the get-go so that kind of negates their status under the well-intentioned umbrella.