Sadly none of the free editors are as well developed as Dorico is at the moment including the new Musescore with it's Dorico "inspired" UI. Dorico's workflow just fits my needs perfectly at the moment.

Reaper and Nuendo aren't really comparable either. Nuendo just has so much engineering behind it for audio post and multichannel (e.g. Atmos) not to mention expression maps and excellent MIDI editing. I do admit Reaper, if it runs on linuxulator, could work quite well as a prototyping tool on the go. Then again Cubasis and Dorico iPad does it too and can import straight to the Desktop versions.

I do wish there were good open source options but, alas. Maybe some day...