If it were me, I would purchase an ART DTI box:https://www.soundonsound.com/reviews/art-dti
...possibly the single most useful device in the whole audio industry! :lol:
This box has two audio channels with the inputs and outputs separated by isolating transformers, and more or less every connector type known to man (or woman).
So... with a bunch of adapter cables to hand, you could unplug the output of the radio mic receiver into the appropriate connector on the input side of the box, and then use one of your handy adapter cables to connect the output of the radio mic into one of the other input-side connectors. That will restore the straight path from radio mic receiver to the venue's PA system.
You then take another cable and connect that to the output side of the box, and run it back to your camera to provide a transformer-isolated split.
The box will take care of any unbalanced/balanced issues, and provide galvanic isolation to avoid ground loops. The fact that it is a low-impedance line level feed from the radio mic receiver means it will be quite happy driving a couple of (relatively) high-impedance destinations without issues.
Note - the output from the DTI box will be the same level that comes out of the receiver... so normally line level, but some might be mic level...
A DTI box is about £50, and you'll need to invest in some appropriate adapters or adapter cables to suit the connections used in the venues you frequent.