I used to use Keepass with auto-type. I had a hotkey for it, and it would recognize the site based on the browser window title.

That would probably be the best of both, no clipboard, and no browser addons.

Some password managers will type the username/password into the browser (through a virtual keyboard I think), not copy-paste them to protect against clipboard attacks. Eg. Keepasssc

There are non-browser-extension password managers that still emulate you typing on your keyboard, rather than going through clipboard.

Personally I use rofi-pass to access GNU pass passwords (so just a hotkey and search for password name)

I'd warmly recommend it (or whatever other client you use for GNU pass) but I'm sure you can find similar functionality for any other decent password manager.

Firefox extension, Passhash NG.

Makes them easy to use, with no saved PW.

I a simple algorithm to generate a password based on the name of the service you are using, interleaved with a constant master password you remember. You can do the same thing with a password-manager password + clipboard, interleaved with a constant master password you remember, which should be even better.

You do realize that in 10 seconds your computer can achieve a lot of stuffs right?

The purpose of clearing clipboard is so you don't accidentally paste it into a chat window or something. Not to protect against malicious programs.