I don’t know that the method by which a signal is transmitted in a transistor is any better than a transformer
A FET works more like a valve/tube.
If you like transimpedance (current based) amps, they are more than likely a BJT.
The problem you are up against using either device above is that the input side of the device is outside of the feedback loop. You will have a rather prodigious electrical peak, likely between 1-5MHz with most LOMC cartridges. It might be as much as 30dB depending on the Q value (how long as opposed to how wide) of the coil in the cartridge. That peak can be energized and easily overload the input despite the use of feedback.
So an SUT has the advantage of not being overloaded in this way and actually blocks the RFI generated in this fashion from reaching the phono stage input! That's a pretty clear advantage!
(The overload can cause ticks and pops as well as distortion which is perceived as brightness- hence the use of 'cartridge loading' resistors, which detune the electrical resonance, preventing it from going into excitation.)
If you're going to run solid state, you need to use an opamp to get around this problem, or set up the feedback look on the discrete devices in the same manner as used in with an opamp; essentially creating a low performance opamp in the process...