I have a 30GB data cap - my biggest iOS 13 problem has been that the photos app used 20GB of data in a week or so (Optimize Storage is on, but I think it was trying to pull stuff down to sync with Google Photos - my backup system) ... I've disabled cellular data for Photos.app so hopefully that'll do it.
Also, apps installed using a different iTunes account than my main account fail to open after 2-3 days and have to be deleted and re-installed, which requires signing out of my main account and, in turn, losing all of my Apple Music downloads - obviously not optimal when I've already blown through my monthly data allowance less than halfway through the billing period. Lol.
Otherwise, the beta has been surprisingly solid in my experience.
I also have 30GB (now 20GB for iPad. Pricey) allowance but I often find myself needing to burn data midway or at the last day because there is no data roll over for plans lol. I do not use Google Drive to backup my photos though, but regularly export photos to my hard drive and upload photos to OneDrive, which then is synced to my main PC, with which a full backup being created every week.
I have two iTunes accounts for two regions (Japan and Australia), with different collection of apps. By far I haven’t notice any app being downloaded with second iTunes account fail to open after two weeks of using beta 1. I guess that is because I often keep the second account logged in as iTunes account.
My iPad now restarts every day at random time when I am not using it. Weird but expected. Other than that, nothing that hurts me a lot.
Almost every app I’ve used now asks if it has permission to use Bluetooth? Not sure why they would need access to Bluetooth so I’ve turned Bluetooth off. Not really a bug but it’s annoying.
Yes. I also want a one-off master switch within Screen Time settings so that I can deny pretty much all access of BT from all apps. I also wish I could deploy some MDM policies to further lock down my iOS to what I like, though I know this is impossible.