Subfloor is rotted and sink into the crawlspace.

I'm living in a generational family home in the Gulf of Mexico, and during Harvey (2017), the entire neighborhood was flooded. At the time, the house was in my Great Uncle's name and not my grandmother's (who was the person living here), and because of that, the only people who would help us at the time (though I wasn't yet living here) were Mormon missionaries who installed laminate floors over particle board and called it done.

Basically, everything they installed in the house, including the appliances, was done on the cheap and was failing at the same time. Though it's hard to be mad at that, the missionaries got us this far.

Compounding issues is a lack of gutters on the roof, however, and now we're dealing with a swamp every time it rains that has gotten into the crawlspace. I'll be honest, it's not good. The house is no longer level, causing cracks in the walls/ceiling, and the doors to misalign. The subfloors are soft and caving in, there's a hole in the living room, and we're walking on wood planks over laminate that's slip-sliding around tissue paper subflooring.

The ideal solution is to bulldoze the entire thing, but abject poverty (and homeowner neglect on our part) got us into this mess in the first place. So I'm trying to figure out what I can do to mitigate even more damage (like flooding) and set us up for success if and when we can get the floor replaced.

I'm posting here to see if a more experienced person could check my work or offer suggestions I'm not seeing because I know nothing at all about construction, but I have to change that fast. From what I can tell, I need to start with a sump pump, then install gutters (though I'm not sure if the house not being level will cause an issue there). The house is in our name now, and we got a loan to jack it back up. After that, I can try my hand at a French drain. And from what I can tell, if I can scrounge that together, I would then need to regrade my yard.