Patio/Foundation Flooding Causing Water in House

My backyard slopes very slightly towards the back of my house so that rainwater flows under the patio and sits after a very heavy rain then slowly drains around the house to the street.

I just stepped into my master bathroom (backs up to the patio) and found standing water from the back wall into the house several feet. This water presumably came up through the slab.

I know I need to do something but I'm not sure what or who to contact. Do I go through a landscape company or others? Not sure if I need to regrade the backyard or just install a few french drains.

Side note: The previous (original) owners previously had an inground pool and filled it in and the slope likely has to do with this earthwork. We just found the walkway around the pool about 1.5' below the current ground surface when digging a hole the other week.

Any help or experience with a similar situation is greatly appreciated!