Clairefontaine engineering gridded notebooks and a non-bleeding pen (and correction tape). Excellent paper quality and the smallish gridded pages work well for me. Slightly larger page size but fits the laptop bag. They have various sizes.

I’ve tried all sorts of programs but the ease of searching pales when compared to the difficulty of using it. It lives at my right hand when working so everything scribbled, recorded or whatever lives in one place.