It really does seem like a lot of people here report bad sheds the first time a new snake sheds with them, even if their humidity is basically fine. Remember that the snake’s body is working on new skin well before you see any visual signs of it, so all sorts of stuff having to do with shipping, moving, adjusting to a new environment, and getting the enclosure dialed in can have an effect. That’s all to say that it’s entirely possible that the next shed will be fine even if this one wasn’t.
Re. humid hides though: IMO, more hides is good and an assortment of hides with different conditions in them is better. That lets the snake choose where it’s comfortable and what conditions it needs. There’s no reason to take the humid hide away after a shed; and actually, if you only put it in while the snake is in shed, the snake is probably less likely to make use of it because it’s new and unfamiliar.
There are lots of ways to make one; for example, you could use a plastic tub with an entrance in the lid, and fill the tub with coco coir or moss or whatever. If it’s deep, it can be damp enough at the bottom to maintain high humidity while the surface stays dry to avoid skin issues from sitting somewhere damp. You don’t have to replace that stuff all that often, just if it gets soiled or starts to look gross.