Symbolism is one we often overlook, and yet it is often the most prevalent one. They make cameras that look like they embody the ideals of the consumer. Boxy and utilitarian was all the rage when the F5/55 came out, and told camera buyers that the F5/55 was a modern and utilitarian tool... they just got so excited about their new fresh design, they forgot a few more traditionally proven ways of doing things. Combine that with manufacturing limitations, or short cuts, whichever, and you get the enigma that is the F55. A good camera that is also a not so great camera? Haha. The blocky design was not particularly adaptable or modular, except for the one option, the R5 and the replacement R7 recorders. So, in the end, the design served little function.
Sony offered VCT-FSA5 from the start.

F55 came quite 0K, if you remember FS700 with HXR-IFR interface and R5 attached.

For two channel slot-in wireless audio, just use DWA-01D digital wireless receiver adaptor.

I use it on with switch set to AES/EBU, both on adaptor and my CANON camera.