Stumbled on this post a few times while trying to figure this out.
I'm using a Lenovo Duet 5 Chromebook and I cannot find a setting to enable autofill in the settings. I cannot find any kind of draw over settings either...
So ... For anyone that also hits the same issue as me this can now be resolved through a setting within the Enpass Android App.
Go to Settings > Autofill
Check the box for "Autofill in Chrome browser (Beta)"
Seems kinda obvious I guess but I had thought it would be more difficult and spent more time than anyone should searching around for a way to make it work.
(and there is of course the 'Android Autofill service' which you'll probably want to tick at the same time too....)
I hope this saves someone some time...