Kylo Ren would've worked fine given he was used for Fortnite and Lucasfilm had allowed the Soul Caliber people to put Starkiller, Darth Vader, and Yoda into one of those games. The crossover isn't an issue. The pivot from the Sequels was also practical given they'd been working on High Republic and we wont have a new Star Wars film for a few years. No need to promote Episode 9 given that marketing push is already done. They promote products in relation to the media they're putting out. Boba Fett had a bunch of merch primed before Season 2 of Mandolorian, he was in the season. Hasbro did a bunch of clone troopers, naturally they ended up in Bad Batch.
If anything yeah, they'd do Mando. But that's because he'd have a TV show coming out. If this was KOTOR they'd use Revan or if it was a re-release of ANH you'd have Luke Skywalker. And even then with Soul Caliber it was because TFU had Starkiller and so was the focus of the crossover (Vader and Yoda had been system exclusives). That's just how they do things. They don't do it because people had a hissy fit over the sequels, they do things that way because that's how they sell products.