I also used to believe in OK-ish to Good Pens but cheap notebooks punctuated with the usual Moleskin, Field Notes, etc. Then I tried some of those Japanese ones -- they are super good and you don't wanna waste and leave no whitespace -- you write and write everywhere.

You should try Midori https://www.midori-japan.co.jp/english/

Now, my idea it to stick to a standard size wherever possible; I've chosen A5 as my go-to Notebook and a mix of a lot of good ones and a few of the best ones.