I tried the following, for my failed to verify message for the public beta 2.
Delete download, multiple times
remove profile, multiple times
reset network settings, multiple times
anything else I could find via a google search, which brought me here.
All of which failed.
I had been starting the download and walking away to do other stuff, like getting ready for work
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. I had an ah ha moment when I looked at the display and it said LTE and not WiFi (brief moment on lock screen) during one of my many tries.
What worked for me was using my iPhone X for 45 minutes straight (slow wifi network connection)
I never let the display dim, or the phone snooze off.
I kept it on and actively working reading news, browsing web pages, playing games etc, the download finished and its installing now. No failed to verify.
Clearly we all are having varied, results but maybe this will work for you. It did for me.
iirc, many years ago I to do a similar thing with ios 4, maybe 5 to get a developer beta to successfully download.
edit: Of course I could have just lucked out, but I also used the same process on my iPad with success.