I use LineageOS with MicroG on my phone. If I quickly press the Power On/Off-button repeatedly it plays an alarm and dials a call for help. This is probably in all android versions, I don’t know.
I know biometric unlocking is dangerous, because it can be forced. But it’s incredible convenient 99,99% of the time. Wouldn’t it be rather easy to implement an option to switch off biometric unlocking when doing the emergency clicking? Or is there already another option? I’m sure I’m not the first genius to think about it.
There is also an alternate app called paranoids pal on fdroid, that’s new and maintained, it did not work reliable on my phone, maybe it works better for you.
And I’ve used private lock for years and still sometimes lock the phone accidentally, but for me the inconvenience is acceptable because of the security gained.