Personally I was looking for this feature when I first started using Logseq, The contents sidebar, (like @cannibalox described) even though it’s not obvious, I think it’s a great implementation of pinnning, starting, marking favorite, shortcuts or any other term used by other apps.
It’s really flexible and super quick to access! The only thing I might suggest is perhaps renaming this to “Favorites” or something more intuitive for beginners. Apart from that I really enjoy the way it works!