I haven’t updated to 15, but I thought they just removed the ability to run unsigned software by right clicking and selecting open. My understanding was you had to manually approve it in the system settings via Gatekeeper?

Apple is 100% slowly boiling the frog in respect to locking down macOS to be like iOS. I already switched to Linux on my personal machines. I saw the writing on the wall when notarization was announced in 2017.