I locked my phone during a false "it's been stolen" panic using Google's device manager.
I chose a nontrivial password. I thought I was safe since I cut-and-pasted the password after first typing it in a text editor.
Now either something is wrong or my fingers are incapable of duplicating this password on the (now found) device itself.
Is there a way to cut-and-paste the password from a computer, rather than on the device itself? The device is in developer mode and is not rooted.
Luckily I had the "Hacker's keyboard" as an option. The default Gboard keyboard does not give any feedback, but this hacker's keyboard flashes the last key pressed. Now I know with certainty that I've typed the password exactly as I had cut-and-pasted it. Hence entering the password on a computer may not help either. I wish they'd have added an "Unlock your phone" feature along with "Lock your phone" on Google's device manager page.
As a reference I'd like to mention here that entering a second password using the GDM is rejected. You're stuck with the first password you chose.
Having a GDM as flawed as this is still better than risking that your private information gets in the hands of random strangers, but be prepared to wipe your phone when you recover it. It may be the only option remaining.