I have also issues with autofill. On many apps the enpass dialog to fill the input fields is not shown. I disabled and enabled autofill a couple of times. I tried 1Password to see if it's an issue in general or only related to enpass. 1password works perfect here.
My Setup is:
Pixel 4
Android 10 (Build: QQ2A.200305.003
Latest version of Enpass