Here is the MINIMUM to get rid of RFI coming in via the cable.
Solder 2 x 22nF or 10nF CERAMIC capacitors between p2 and the Ground Tag and p3 and the Ground Tag. The leads MUST be as SHORT AS POSSIBLE.
I only show the CERAMIC on p2 cos your p3 is under the PCB. You'll have to work out how to connect the p3 CERAMIC to the Ground Tag with short leads.
Next put Ferrite Beads on the leads (or better still lossy inductors) between p2 & p3 and the PCB.
View attachment 124021
This is the scheme I used on the Calrec stick mikes and Dip. Ing Wuttke used for Schoeps.
The CERAMICS are C12 & 13 on the CMC5 circuit
https://groupdiy.com/threads/schoeps-cmc5-inductor-values.73321/
and the lossy inductors are Dr3 & 4
They MUST be AT the XLR. Check that the Ground Tag makes a REALLY GOOD CONNECTION to the mike body. Try to shorten the transformer output leads or at least twist them tightly together.
You may or may not need extra work on the grille, FET etc that various people here have suggested, but without the above mods, you WILL have RFI problems.