Let’s look at it this way. What races today would Merckx realistic win in his peak form?
That idea only makes sense if you teleport him in this era and give him access to modern training, nutrition and rest.
Vice versa, teleportating Pogacar into Merckx era would only serve a purpose in comparison if he'd have to to this eras training, nutrition, race load etc.
Ofc you can wonder what Merckx from the 70ies would do, but what would we learn from that?
Btw.: is there any knowledge on how many watts he could push? Also with the racing schedule, what kind of peak are we talking about?