I have run every developer beta for the past 5 years, at least.
This first developer beta is by FAR the most stable first iOS beta ever released - in fact, it's far more stable than the iOS 13 GM that SHIPPED last year.
Apple clearly learned from the complaints over last years stability - and granted, there aren't really many new features this year.
But that being said after a few days of heavy use, and of course, install at your own risk but...
I would say this first developer beta is more than stable enough for your daily driver.
This first developer beta is by FAR the most stable first iOS beta ever released - in fact, it's far more stable than the iOS 13 GM that SHIPPED last year.
Apple clearly learned from the complaints over last years stability - and granted, there aren't really many new features this year.
But that being said after a few days of heavy use, and of course, install at your own risk but...
I would say this first developer beta is more than stable enough for your daily driver.