If she likes the taste of juice and will drink it from a dropper/syringe then you've got it easy, as you can give her flavored Pedialyte (or the generic store brand, I buy Walmart brand). I usually buy the unflavored Pedialyte to mix with slurries when my rescue guy or my parrots ares sick or impacted, but I found that my rescue guy likes the grape flavor a lot, so I can actually just drip it onto his snout and he'll drink a ton of it. I even put some in a bowl and he drinks a ton of it (he's the only beardie I've ever had that I've seen drink water out of a bowl, so I tried the grape Pedialyte). It's sugar-free and has no citric acid in it.
Beardies should get all the
hydration they need from both their greens/veggies/occasional fruit and their live feeder insects (if you gut-load your feeders with greens, veggies, and fruit and then feed them to your beardie they get everything the feeders just ate). So you shouldn't need to give additional
hydration to your beardie if his diet is complete, but if you still feel it necessary then that's fine to give her water or the flavored Pedialyte if she likes it. I'm glad you understand that baths do no good at all unless they actively drink the water, as
hydration has to go in through their mouths, not their vents or scales/skin. Soaking them in a
bath does nothing for
hydration unless they drink the water, so pouring Pedialyte into a
bath and letting them soak in it does nothing but wasting the Pedialyte. But if your beardie likes orange juice, try orange flavored Pedialyte, or any other flavors, they're all safe and she'll get electrolytes too...