I am taking a byte string of hex values and translating them into DCC bit stream messages. This is then ‘amplified’ up to ~14.8v with a ~5A current capacity

I coded this so you can send any dcc message out. However, the layer above this, the IoT layer, only supports the basics. Throttle and Function Codes only. So this means you have to program the decoder with an alternate system, the widget doesn’t yet support that. I use the Prodigy Express by MRC, it was like $100 or so. Works great on all the decoders I have tried so far.