It can be done. I did it in reverse. I had the extendable mirrors and didn't like them.
Having said all of that, I replaced my extendable mirrors on a 2017 Titan SL with tow package, with the regular style mirrors on the Titan SL without the Tow Package. All the options I had before were retained. The mirrors I now have also had the power folding feature and I think I can get that by changing the Switch Assembly Mirror Control to the one that is on the regular SL because I believe the harnesses will have the wires in them.
I think it may have been significant that I exchanged with the same model - SL (w/tow pkg) and SL (without Tow Package). I don't know what functions you have in your existing mirrors. Does the Pro4X also come with the towing package?What I did was to look up the VIN numbers for SL's without the tow package, and order the mirrors that were OEM for that model, looking at the Window Stickers online on SL's for sale with the same mirror features I had.
I don't know what mirror features you have on your Pro4X, if any. I could sell you my old mirrors. They are on Ebay right now as a set, but I don't know what functions you would get if you don't have the same functions now. I have lane change warning light, puddle light, memory, heated, power adjustment.