What happened with ITU Resolution COM6/19 ? This problem was recognized in 2015 or earlier and should have been addressed at WRC 2019.
Against the odds we were largely successful, due to a huge effort by many, in identifying spectrum for short duration missions. The result was:
The frequency band 137.025–138 MHz may be used for short-duration missions, if they do not cause harmful interference and if they do not claim protection from other services. In this case, simplified filing procedures apply. For most countries, the coordination requirement Art. 9.21 was removed from the uplink band 148–149.9 MHz which enables it's use for these missions.
It's not perfect but a good outcome given the circumstances.