I had no problems with the original release of iOS 13. In fact, the original release (in my experience) seemed to be an improvement over 12.x for that week or so i had it.
The past couple of updates though - oh my, what a disaster.
Main issue(s) are with Carplay in particular. Waze (and/or maps - i think anything using the GPS) will just.... stop working. Phone will get super hot, freeze and literally 5-10 minutes later either crash/reboot - or suddenly recover and carry on. And you won't notice unless you happen to see the map isn't updating. Which makes relying on navigation instructions, traffic/accident/camera alerts, etc. - totally useless.
Which is.... annoying.
edit:
actually, last weekend, the phone drained battery super fast while i left it somewhere else in the house. it died. i'm guessing maybe something else on it went AWOL and froze/chewed hell out of the battery until it went flat, whilst unattended. It would have chewed 50% plus whilst unattended in say 3-4 hours. I only found out because my GF was knocking on the front door to be let into the house (she went for a run without house keys) after trying to call me and not getting a response.
Battery is "normal" condition... iphone 7...