This makes using a password manager super annoying, because I have to trigger the autofill twice.

Some - if not most - password managers let you configure the auto-type-sequence for each password individually (e.g. KeePassXC). Just change the default {USERNAME}{TAB}{PASSWORD}{ENTER} to {USERNAME}{ENTER}{DELAY X}{PASSWORD}{ENTER} with X being a delay in milliseconds that pauses the sequence until the new page has loaded completely.

“Let me speak to your manager!” - Karen Musk, 2023