16 Pro Max still working fine, I listened to the presentation but did not hear any mention of whether the spatial / 3D (which I have used a grand total of two or three times but still think is a great thing) is still a supported feature in any of these new devices. We typically only get the even-numbered editions, not intentionally that's just the way it's worked out.
And regarding carriers, I always buy unlocked and my carrier is US Mobile. I have two eSIMs, one on Verizon "Warp" and one on ATT "Dark Star" and if I'm ever in an area where one of them has zero signal, data usage swaps automagically to the other. We don't need overpriced unlimited data, 10GB shared between our two iPhones, (mine with 2 sims) plus three no-data devices is $60/month.
We are, however, going to be getting the new Watch 11. We have series 6 now, the batteries are shot and best I can determine, far less hassle to upgrade than try to replace the batteries.