Help With Recent Rescue

This is going to be long, I'm so sorry. I'm hoping someone reasonable in the dog world can help or has some thoughts or ideas for us! We adopted a 3-5 year old dog from a local shelter in February after our child had been asking for a dog for quite some time and was ready for the responsibility. Our child was so excited to get their "own dog" (it's a family dog, spouse and I knew that going into it and are fine with it). We've had two other rescue dogs in the past, the last one passed away a couple of years ago. Our new dog is a great dog to our nuclear family, very sweet and loving toward us. But the dog we thought we were bringing home is very different than how things have turned out. When we adopted her, she had been in the shelter for about 2 months, and the only thing they told us was that she does not get along with cats, which is no problem, we aren't a cat household. They had no other notes about her or any issues to report.

We learned very quickly that she has a large amount of fear-based aggression. She snarls, barks, and lunges at other dogs on walks, at other people out on walks, on anyone on wheels, and charges the fence and kicks up dirt and barks/growls when other dogs or people walk by our yard if she is outside. We have changed her walk schedule, don't take her to populated areas or to walk in our neighborhood park to avoid interactions, and have modified how and who we host in our home. She does okay with people who come into the house after a safe and proper introduction while leashed, but we never know for sure how she will do, and she has snapped at my dad twice (only him, we haven't been able to figure out what triggers her, there doesn't seem to be any rhyme or reason). She is also afraid to walk on our wood floors and is terrified to the point of continuous panting, pacing, and ongoing explosive diarrhea during thunderstorms, even while using a thunder shirt and medications from the vet.

We are working with a trainer every other week, which is nice but doesn't feel like it's manageable honestly. It's also $$$. Spouse and I work fulltime outside of the house and our child is at school and has activities in the evenings/weekends. We are certainly home enough and have enough flexibility to accommodate a dog, but probably not as much as we should have to accommodate the needs of this dog in conjunction with training as well. I also now am facing the reality that we can never travel while she is part of our family or use a dog walker because I'm terrified of her reacting to someone and causing harm. I won't take her to get groomed because of her reactiveness, Spouse and I are terrified when we have to take her to the vet, and I panic when the cleaning lady is coming for the day because I'm terrified that the dog will react while we are gone and she is there. She did fine with the cleaning lady last time but I never trust that one time will mimic the other. I know that things take time, but her anxiety triggers mine and it's been hard for our child to bond with her because she is so fear focused that she rarely plays or does anything but be on alert to threats. When the weather is nice and no one and nothing is making sounds outside and the stars align, things are fine.

I don't want to not have her as our dog, but I also don't feel comfortable and confident as her human and I'm not sure how to get to that point. I feel like hard times (early morning thunderstorms combined with power outage were rough today) really magnify the issues as well on my part. I don't even know what our next steps are. Obviously, there is no magic fix. Any advice, or here's what you need to do, or pet behavior folks who can chime in and help us with some direction and thoughts would be so appreciated