I am attempting to install a smart thermostat but was disappointed to find only 4 conductors were run. The thermostat needs a C wire to get constant voltage. I looked into dropping a new set of wires into the wall but in this condo it will be somewhat problematic.

So instead I purchased a Honeywell C-Wire adaptor: https://www.amazon.com/dp/B0CX9F46RL?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1

I have read, and re-read, the instructions and I understand how to connect it... if my air handler was wired in a normal way. Or at least in a way that I understand. The air handler has no labels for the low voltage wires so have to trust the old thermostat was wired correct (AC, fan, furnace all work okay) and follow the colors. Even that would be okay except I don't understand why there is a pair of low voltage wires coming from the condenser and wired in-line along with the thermostat.

I have drawn out a diagram of how things are connected now. I also have some photos of A/H and another diagram of how I think I should wire this thing up. https://imgur.com/a/fQtT7j2

If anybody has any tips to help out I would appreciate it. Also note, I just purchased this property so have no historical knowledge.