My main use of notebooks is for journaling.
I currently use a Rhodia Webbie Dot Grid A5 notebook. I bought a multipack of these years ago and have been overall quite happy with the quality. The cover is solid and feels nice, the paper is 90g ivory, and the notebook sits flat. There’s also a ribbon for keeping track of your current page and an elastic strap to keep the notebook closed.
The main drawback is the dot pattern is very small at 5mm, which can make my notes look like a mess.
My next notebook will be a Leuchtturm1917 Medium A5 Dotted notebook. It’s gotten very good reviews and is slightly cheaper. The cover doesn’t feel as nice, but everything else about it seems great.