Bill ... surprised at your not getting the Protosound 3 MTH F-3 to run with the DCS Remote Commander.
Ref my week-ago post in the S-gauge sub-forum of OGR about adding DCS Explorer to my vintage Gilbert tubular track layout that was successful ... https://ogrforum.ogaugerr.com/...ntage-gilbert-layout .
Upon reading your original 18 Dec post above and Banjoflyer's above post on passively wiring the Remote Commander, I opted to buy a DCS Remote Commander and give it a try with its own handheld remote ... liked the passive wiring feature of the Remote Commander and a physical handheld remote and not needing to get a smart device hooked up to wifi in order to use it. Plus the DCS Explorer takes about a minute to go through its start up until it emits a wifi signal, then one has to go through wifi connection steps on their smart device, etc. Then, if one loses power, the DCS Explorer / smart device have to go through all of that all over again. Those are all extra steps that aren't needed when using the Remote Commander in passive mode. I didn't fully appreciate that when I first went with the DCS Explorer. So, I'm now running DCS on my layout via Remote Commander passively wired to the input side of my Atlas 215 SPDT switch array for the positive rail track connection and ground connection to my common ground bus for my overall track layout. As with the DCS Explorer experience, I'm running my Legacy/TMCC locos simultaneously via their respective controls while separately controlling the MTH F-3 with it Remote Commander hand held remote. I have not experienced any interference between the two control systems so far.
Factory Reset of Engine ID: I did the required factory reset of engine ID using an MTH subscreen on my smart device using my DCS Explorer and that, in turn, enabled me to communicate with my Protosound 3 MTH F-3 with my new DCS Remote Commander. I did that for the two Protosound 3 MTH F-3 engines that I have and both are now controllable via my Remote Commander remote ... one engine at a time, which is an acceptable-to-me limitation of the Remote Commander. For my limited Protosound 3 MTH F-3 train-running, I actually now prefer not having to deal with the smart device most of the time ... holding the handheld remote is my preferred control option. Didn't quite appreciate that when I went with the DCS Explorer originally ... that's ok though as the Explorer does enable 2-engine control and has some added features such as Factory Engine Reset which I didn't know I'd need till now.
Anyway, perhaps your Factory Reset method didn't actually result in a factory reset. I did read in Barry B's DCS Companion 3rd Ed, pg 204 ... "New PS3 engines ... may have the capability to perform a Factory Reset through a combination of button presses (SND, DIR,-)" on the Remote Commander. As noted above, I didn't do my Factory Reset using the Remote Commander; I used my DCS Explorer which has a specific menu item for doing a Factory Reset. Perhaps there is a colleague who has the ability to do a factory reset nearby where you could take your engine. I do like the Remote Commander / Hand Held Remote Control for running my Protosound 3 MTH F-3s, one at a time. I think you would too ... they are nice-running and nice-featured engines with cruise and good engine sounds and crew dialogue.