het x het is always going to be a stronger/healthier bloodline when bloodlines are relatively new like they are with zeros/wits/weros. But as time goes on, and the bloodlines strengthen and diversify, that becomes less and less of an issue.
That's where breeder selection really comes into play. Are you buying from a breeder who has been working the bloodline for years/decades? Or are you buying a bloodline from a breeder who is only 1 or 2 generations in with their breeding program. Typically, the earlier in a breeding program a bloodline is, the weaker (health wise) it will be (when referring to newer morphs).
A lot of "new" breeders try to get into the game too quick, and the only way to do that is with bad pairings. So just because a breeder says that your clutch is from a visXhet pairing, was that mom or dad the result of visXvis pairings? And how far up the line does that go?
Most breeders won't be giving you a family history of the line besides who the parents are, which is why buying from a reputable trusted breeder is the best thing you can do to ensure a healthy reptile, along with being well versed on genetics.