I have just read this wonderful news:
tl;dr Synapse supports python 3 since 0.34.0, with massive perf wins.
Please update Synapse to Python 3.
Technically this is blocked by python-affinity and python-matrix-synapse-ldap3 packages, but maybe they are no longer needed or can be updated as well.
Other packages will get unblocked for Python 2 removal by this.
It looks like affinity is no longer a dependency and I built python-matrix-synapse-ldap3 for Python 3. I've updated Rawhide to 0.34 and swapped it over to use Python 3.
python2-matrix-synapse-ldap3 is not needed