2003 D2 HSE - sat indoors for 14 years parked due to HG

No gears shown in cluster, not P, R, N, D, or 3-2-1. Not shown in center console either. Stuck in 3rd gear plus flashing M+S lights so likely not in "manual transmission" setting? Not sure how to check this. I got rid of my Nanocom. Only have a Launch.

Can see gear position in BCU on live data - shift interlock works in park and neutral, reverse lights and parking sensors activate in reverse. Immobilizer is working fine, enables with lock, disables with unlock. No other BCU symptoms, windows, lights, central locking etc all work. --EDIT-- I can not see "P R N D" in BCU any more, only that reverse and park/neutral are engaged.

From what I can see, the chain goes from XYZ switch, to BCU, to IDM fuse box, then cluster, then center console - never interfacing with TCU. But I'm not certain in this. Have seen opposing information throughout my manual. Mainly XYZ to BCU to cluster.

Have done basics so far
0. Checked voltages, all good - checked and cleaned engine bay grounds, also good. New AGM group 65 battery as of today.
1. Have rebuilt and checked XYZ switch
2. Checked all fuses
3. Checked for corrosion everywhere I can. ECU, SLABS, TCU, IDM, and BCU. No corrosion found anywhere.
4. Checked for any signs of rodents, none noted.

Going to swap random parts tomorrow. Well, TCU and IDM fuse box. I have spares of both so why not I guess? May try and swap in BCU/ECU/cluster combo from my friends truck.