I have worked with lots of rescues. The soaking is likely to keep the fluids up vet journals often speak of dehydration in reptiles being a serious emergency where even 5 years ago not so much. The soaking is a tough call stress is also very serious.

You have separated them yes? The first CRITICAL thing is to keep the temps correct. she is small so I'd say 89-90 (88 is fine under normal conditions these are not.) with 78-9 cool side and ambient around 80-83º ambient likely is very important in this case. I'd suggest giving her a break for a few days no soaks no feeding nothing just quiet and dark.

I would try to get the humidity up to around 65%-75% RH. Remember that ventilation is also important as well. You might find a humid hide maybe better than soaking less stress and similar effect. Talk with your vet.

Tube feeding with a pinky pump or critical care? Necessary? I can't say I am not there. That is quite serious weight loss and to me that is critical at this point. Again it is a balance between intervention and stress. It is hard to know what is the right choice vets tend to like to do something. In fairness the client generally don't accept do nothing as the correct action. If you present that as your suggestion it returns it to the table as a viable option. I would discuss the situation with your vet and ask after the concerns about stress.