2 words for you: Password Manager

Get around to using one :P

I only remember my password to my PW manager, which additionally is encrypted with a key file to increase security.

The rest of my PWs are 128 character long random generated PWs, with capitals, numbers, special characters etc…

Where do you keep the key file and the PW managers DB? I feel like they would be too much side-by-side to really increase security in my case

You could use a USB drive that you only ever plug in to open the password manager. It’s not the most secure option but it’s a bit better than no key file at all.