I installed the Public Beta last night on my XS Max and all seemed ok, but unfortunately for me in the UK on Vodafone the status bar used to show "vodafone 4G" as my carrier and started showing "vodafone LTE" which isn't the end of the world as data access worked. However, iMessage from my phone number refused to activate. I only had the availability to iMessage from my email address no matter what I tried, rebooting, resetting, taking out SIM, turning off iMessage etc. Calls were fine, but I also couldn't send a regular SMS to a non-iPhone user as it just instantly failed.
I could have lived with that, but the kicker was the fact that all smart notifications to my Garmin Fenix 5 Plus watch stopped. I re-paired, re-installed and did all the usual but all notifications broke and I couldn't resolve so I went back to iOS 12.4.