I don’t think I completely agree about spending on new builds. The other lines are under similar pressures from debt. (Granted Carnival is a little deeper) and have invested in new builds. I think they could announce a new build for Carnival before the end of 2025.
I also think the XL class was definitely a move to offer something closer to the Oasis class. Much larger capacity than any previous Carnival ship, zones (neighborhoods). I also agree they are not trying to directly match but rather have a competitive product to what other lines like Royal are offering.