Spearo suits typically have no zips but I suppose you could order one with zips. They typically need to be lubed before you wrestle them on, although special lube-free linings are available at extra cost which some forum members like.
Trim your finger nails or risk gouging the soft, open cell interior with little Cresent-shaped cuts when you put the suit on or take it off.
As others have already said harder neoprenes ate usually used for SCUBA suits, to better retain loft (insulation) when staying down for extended periods. Maker Eliossub pointed this out to me when I ordered my first made-to-measure spearo wetsuit, their point being that there inexpensive Ecoline neoprene is more than adequate for spearing; their fancier more expensive neoprenes are aimed at SCUBA divers. Ecoline is not that soft or stretchy compared to off-the-shelf spearo suits though.
If you want a suit exclusively for SCUBA (?), wouldn't a dry suit make more sense? "Horses for courses". A former colleague and friend was a PADI instructor instructor (i.e. he trained other instructors) and he used a dry suit as he could wear warm clothing inside it e.g. a sweatshirt!.