I don't have much I want to bring up to my manager in 1:1s but I still prefer to have them as a manager myself. So 1:1s definitely never felt unreasonably effective. Never thought to optimize it tho.

Anything of value or importance has to be written down, it is a short objective statement, usually a few lines. And then pursuing those over time (1 to several weeks or months) and having accountability check-ins. This would make 1:1s very formal and 1:1s usually seem better as casual conversations.