Simple reality:
If you want a vintage enema bag or bulb douche, you buy used or not at all. Your chances of finding truly “new, unused” bags and bulbs is about as good as a big lottery win. About the only realistic chance is from the stock of a long closed and abandoned, likely small town, pharmacy.
Virtually nobody ever bought a bag or bulb ‘just to have one’. Bags were usually bought because someone in the family, usually a kid, was in need of drastic intervention to MAKE them poo or a woman had an infection or wanted to douche after sex. Bags and bulbs are purpose made. If you want to delude yourself, buy a combination syringe and believe it was bought ‘just in case’ and all that was ever used was the hot water bottle part.
In a capsule: Buy second hand and assume it has been used and needs a full sanitizing or do without. Period.
While some sellers advertise syringes as ‘new’, ‘NOS’, ‘NIB’, etc. odds are better than 99% ANY syringe has been used.
If the hose is shown attached to the bag, it has been used… 100%
If thee is a nozzle attached to the hose, it has been used… 100%
If the bag is ‘still attached to the box’ it means nothing.
I've described how I clean pre-owned stuff in other posts. I have no concerns about using anything cleaned as described to put solution up anyone's butt, including my own.
YMMV.