Technically this is a deleted scene that Ryan Reynolds dropped post-release. I believe it's show in really low-res cut-up section of this scene on one of the TVA screens, but I'm not sure if enough made it into the movie to be officially canon. Though of course canonicity means little given the multiverse.
Regardless, D&W implied he'd be rescued by the TVA (along with Blade and Elektra, presuming they survived too). That would seemingly put him on a different "team" than the other X-Men that we're going to get. Or, at the very least, the Beast introduced at the end of The Marvels is from a different universe than the Gambit introduced in D&W. Kinda has to be. I mean, I know Gambit was technically in X-Men Origins: Wolverine, but it's pretty heavily implied that the Gambit we met in D&W is from a pruned timeline.
I'd love if we get introduced to Gambit as Mobius's new partner or something in Doomsday (really seems like the TVA needs to be involved, and we have to see Loki somehow), though that would kind of require a lot of other characters being dragged in.
If Gambit's timeline was pruned then they had no 'legitimate' timeline to return him to. And since the new TVA is kinder and gentler they wouldn't force him to stay in the TVA, so they'd have to send him to some other timeline. The Deadpool one would make sense, but since he wasn't at Deadpool's party it's possible they sent him to a timeline that was as close as possible to his own. He can easily be part of the Beast/Monica team