I've had a few different types of electric trailer dollies. My 1st one was a "Power Caster PC-3". It was a 110v, single inflatable tire, power mover and it moved my TrailManor easily (but extremely slowly) on flat, dry concrete. That one cost me about $1500. I now have a 12V (operates on the TM battery), single wheel power mover and it does equally as well moving my TM (faster) on flat concrete and even if it's wet or a slight upgrade. It is a LOT cheaper too. It costs about $250.
The problem that ALL of the power movers have is
TRACTION. Most of them will move your TM with power to spare but most fail when it comes to traction and that's where you are going to find your biggest challenge.
You can find some that have lots of power and large inflatable tires that will do the job but you may find it cheaper and cleaner to have a concrete pad poured where you navigate your trailer, after your truck moves it as far as it can.
If you really want a power mover that can move your tailer over any kind of soil, you will want to find one with 2 large inflatable tires and a LOT of power. I saw one recently that was remote control and the mover had tracks. In my mind, that the ultimate mover.