Part of learning to eliminate on the potty is leaning the ability to associate relaxing the pelvic floor when actually over the toilet. Keep working with her on making the actual sitting on the toilet as commonplace and "no big deal" as possible. If the diapers disappear she'll realize the pee and poop has to go somewhere, and the floor isn't where it goes.
It is so hard!! :-) ((hugs))
As much as you can, keep reminding yourself that this is a positive and fun transition. Kiddos sense our frustration and annoyance and the hiding behavior is because they're feeling the need to "hide" their elimination bc it's causing mommy/daddy so much distress.
What helped with our son was we actually quarantined him off in a "nakey zone" for the first few days of "boot camp" potty training. There was nowhere to hide, no diapers to sit in, no furniture to ruin. Just some hard floor, one little rug and a bunch of washable toys and tv. For better or worse, tv was super helpful for my kiddo bc it was the only thing he'd sit still for lo enough to relax and poop. Lol.
We kept our prefolds/flats around to sop up pee accidents and I used a pet accident enzyme cleaner (from petco) to spray on carpet when it got peed on. No stink or stain leftover and it's safe for kids and pets. And knowing that we had the tools to clean up accidents took all the pressure off.
It still took us months for my son to get through a full day without a pee accident. Some kids reallyget it right away. Others take a lot longer.
Potty training is not a race or a competition to see who "wins" or who the best parent is. So don't beat yourself up.