Why can't I see recipes?
The compression of individual items is hidden and is done automatically in the autocompressor.

Why does the techs shows no recipes beyond 2?
Because with all the mods and structures it would be incredibly cluttered and unlock recipes you really shouldn't have access to yet judging by the rest of the tech tree. So it is all hidden and unlocked as do tech where it checks things and enables it.

Is it the same for the compressed entities?
Yes

Aren't those compressed entities OP?
It is really late game and you decide by what factor, so it is only by your choice really. Besides, they cost slightly more than they taste.