12.1.3b2 .. XS Max 128.
I'm noticing an issue -- which was in the previous beta too (not sure about GA) where my photo library is slow to add a photo.
For example if I take a screenshot it will not appear in the camera roll for quite a while (30 mins+).
Immediately after a screenshot I can click on the bottom left preview to edit, but it will sit on 'preparing' or similar seemingly indefinately. Sometimes the preview doesn't appear.
Other apps seem fine, the phone is snappy. I'm on wifi. Mobile data is enabled for photo too, optimize phone storage, shared albums all enabled, but I did recently switch off photo stream
The photos do come up eventually. I also checked my mac and they are all there too (I'm using iCloud)
Selecting existing photos in apps tends to add a short freeze (10s) to the app too, so there does seem some issue more generally with photos in particular..