I don't get folks claiming that Camelot lost much of the RPG team. I've looked at both the credits of various games, from GS to prior sport games and compared them to recent entries, and basically virtually all of them were still there. That and I just tried digging through Wayback to see what their numbers were throughout the years and really... not much more than now. If anything they peaked at possibly 45 a few years ago but now for whatever reason are at 38, but didn't someone claim a chunk moved to Nintendo internally?
On that note, we have actually a crazy example in support of all this; Yooka-Laylee. SOMEHOW, Playtonic managed to make a full 3D open platformer in the style of Banjo (literally) with I think at peak at around two dozen people, lowest in the beginning at only 6, and did it all including with it being Kickstarted in only two years. Like... Playtonic actually fucking did it and basically did what they did during the N64 era and put out a big-ish game with a small team and while sadly not a banger wasn't shit or unpolished either. Team17 had their own team do the PS4 and XBO ports while Playtonic after did the Switch port in-house (the game was built exclusively for PC on Unity).
So surely Camelot with 38 people, with Nintendo's own power, money, and resources at their disposal, are capable of making a proper 3D Golden Sun, especially if it's say a remake of the two GBA titles as one game as it was meant to be? I don't see how it's so unlikely. Xenoblade, it is not. Golden Sun doesn't NEED to be super big and complex. And who's to say another dev like 8ing or something can't join in to take some of the programming burden off of Camelot?