You can check various threads in the forum to see if it is usable or not.
As of the security, the iOS 13 beta is jailbroken.
https://www.redmondpie.com/jailbreak-ios-13-beta-demoed-by-developer/amp/
It otherwise sports the same iOS security feature from iOS 12.
Although I mostly stopped jailbreaking my iOS devices back after the iPhone 4 (iOS 4!), because it ticked off the boxes for most of the essentials without introducing unnecessary risk, I have always appreciated the ingenuity shown by the jailbreak community.
Apple have spent many, many millions of dollars with hundreds or thousands of incredibly smart people trying to making an OS that tries to avoid the traditional pitfalls of operating system security. Trying to achieve something that is perfectly unbreakable. They've mostly failed. Nearly every (or actually every? I don't keep up like I used to) version has been jailbroken to a greater (untethered) or lesser (tethered) extent.
If you have an engineering mindset you have to appreciate the sheer persistence and ingenuity of the people that keep finding these vulnerabilities.
