I don't think that sounds especially unusual for a pup of that age - especially one whose bladder has been battered around a bit by a UTI. Even if it's fully cleared up (which it may or may not be), the effects on her bladder muscles may take a little longer to repair.
Thing is, if you KNOW she's going to need to pee again 30 minutes after the last trip outside - well, that's how often you need to take her out. She isn't going to learn to potty outside otherwise. Frustrating as it may be, it's her individual
actual needs that you have to work around - not the length of time you might hope she could last.
3-4 hours is the maximum you could hope for with a pup this age crated during the day (so if you're getting 3, I don't see anything terribly unusual or concerning). But it really all boils down to individual limits - know what they are for your pup, and ensure that she gets a proper potty break
before her limit is reached. In the long run, it's better for both of you. Unpleasantness aside, every time she ends sitting in her own pee will lower her inhibitions about doing so - and you can finally end with a dog you've actually trained to potty in the crate. That's far more frustrating than slow potty training

and is actually very diffficult to untrain. So better to just bite the bullet now and get her outside a little more often than she seems to need.
On the upside - it
will get better. UTIs are an absolute curse when you're trying to potty train - but if you think about it, it's no surprise that the pup doesn't learn much when pottying is such an uncomfortable and unpredictable (even for her) event. So, you've had that setback, and it may still be having some effects on her ability to control her bladder. No big deal really - you just have to treat her as you would a slightly younger pup. But if the infection is now treated, she will be able to begin to learn. And her bladder will be getting bigger as she grows too. So things can start to look brighter - you just have to get through the initial stages first
