It just feels like a lot to accommodate a what by most estimations looks like a good-not-great bat?
I'm probably overstating how likely it is that one of PCA, Canario, Alcantara, etc. are a first division starter within the next 18 months. But even if you want to pick apart the internal options, it's just not that hard to find a CF on the market currently. Tyler O'neill, Manuel Margot, Cedric Mullins, Mike Yastrzemski, and Trent Grisham all hit the FA next offseason or the offseason after (and thus potentially the trade block before that). I'd prefer Bellinger to any of those guys, but not by enough to lock into 2027-2029 Bellinger.
Mainly I think you're just more bullish on Bellinger's bat than I am. The juice is worth the squeeze for a ~125 wRC+ where it's just simply not for a ~110. The argument for the former isn't crazy. You've laid out some good points previously, and there's also the Isaac Paredes pulled flyballs stuff. But the totality of what I've seen has me expecting the latter.