Playback of dynamics in an imported MIDI file

Musescore 4: I have some files derived from midi and am trying to get dynamics markings to affect playback. e.g. I want sections marked pp to play back quieter than sections marked ff.
I have found the support article "How to restore correct playback of dynamics and hairpins in an imported MIDI file". This says:
"To fix the problem in MuseScore 2, 3 or 4: .....
In the Note section of the Inspector Properties in Mu4), locate the "Velocity Type" (not available in Mu4) and "Velocity" ... Click on the "Reset to default" buttons for both values."

I realise I need "Properties" not "Inspector". But in Properties I cannot find "Velocity Type": it does indeed appear to be "not available". So what should I look for?
I have used "Playback" in Properties to Reset the Velocity of all the notes, but this just gives them all the same loudness on playback.
I have also tried cutting & pasting pieces of the score to a new file. But this changes nothing.
A workaround is to export as .mxl, load in Musescore3, reset "Velocity Type" and "Velocity" as per the article above, save as .mscz & reload into Musescore4. Surely there is an easier way.