If it's G1 Optimus Prime transformation is really quite basic (even a cake can do it*) but it's a Movie design?!
The Lego Voltron set need a bit of partforming (Well parts removal technically) on the black lion but otherwise converted and combined as you'd expect.
(*For some reason that cake was going around on Twitter a lot over the weekend, even though it's from 7 years ago - the birthday boy is a teenager now.)
My understanding is it's based on ROTB Prime, which from what we've seen so far is basically Geewun. So it could have a fairly simple transformation - flip the back of the truck/legs down, pull arms out of the back of the cab, flip up the head and you're good. I know SS BumblePrime made it more complicated than that but I don't expect a Lego to be on that level. It could work is what I'm saying.
Looking to buy lucky draw Armada Prime and Diaclone Marlboor Wheeljack.
Hasbro should have let Lego make Transformers based sets since all the way back in the days when Built to Rule was a thing.
I have a list of all G1 characters that have been released in CHUG form. You can find it here. Please feel free to let me know if I got anything wrong so I can fix it.
I once made a G1 Prime out of cardboard, tape & those little gold pins you'd push through and split the pin down the middle to act as swivels.
I was bored at work.
Lego should do this with their eyes closed.