When I’m making a new password for my manager I will actually write it down on paper, then type it over and over again until I can type it from memory, and then practice that every now and then (and if I’m not feeling sure, I’d probably make sure my password manager asks me for it every time and that I use my password manager often enough to keep training it)

But like, that’s enough for my brain, and I’m not you. I wish you luck in finding a system that works!