If the web browser is governing the passwords you can and can't have, and forcing you to have unmemorisable passwords, you're better off rethinking the whole thing. For instance, it probably makes more sense to ask the web browser to generate keypairs rather than passwords if we know the passwords cannot possibly be memorised.
I don't reuse passwords, or use a password manager. I just have a system for remembering which password to use for each website, and maintain a list of hints. And I have a pretty terrible memory. But having had the password I used to re-use across a few (non- critical) sites show up on haveibeenpwned it's what works best for me.
