what now?
Rarely, but happens (my experience with the MnM). Two answers:
The funny one:
“Get one more!”
The sad one: “These machines are really complex, why did you guys from Elektron did this bad thing to us?!” 
I am really curious, as it is annoying - no way to expand it or just play with the locks a bit more in order to reduce their number?
Real-time recording can end up creating a lot of unused or unnecessary p-locks, especially on the Monomachine.
You can clean up unnecessary p-locks by going into step-record mode and pressing knobs to clear various locks.
If you have something p-locked on many steps in the same pattern then you should consider saving a new kit, and just p-lock the stuff that is truly different.
Cleaning up unneccessary locks is a pain, but the only way to make other parameters available.
From the manual:
A pattern can have a total of 64 individually locked parameters divided freely between all tracks and parameters. When a parameter is locked on one step, that parameter can be locked to individual values on all the steps of the track.