I would be careful to expect some sort of blow out of support from third parties when it comes to any Nintendo console. At the end of the day Nintendo consoles are first party driven, third parties are committed to PC, PS and Xbox pipeline. And AAA publishers are increasing their ambition and making CPU heavy games like MH Wilds and GTA 6 that in all likelihood will never come to Switch 2.
I think Switch 2 can increase third party support, in that studios like Atlus that mostly skipped porting their games to Switch may port more games to Switch 2, but its clear that Capcom and others won't take Switch 2 into account when they make a new AAA game. I still think that late ports will be much more common than day and date releases of big third party games, and many will skip even a late port and not port the game at all to Switch 2.