Houston tx foundation issues, repairs, drainage and other solutions for clay soil.

We bought a house here build on Clay soil (like everyone else), house had exterior foundation repairs (all around perimeter). We thought nothing of it since repairs are under lifetime warranty! Well, after drought summer I saw crown molding splitting and lines along where wall meets the ceiling. After 2 companies coming out – our house sagged in the middle and 2 inches lower on one side (sank in). We can’t raise it without supporting the middle (aka 15 interior piers that are not under any warranty of foundation company). Going after sellers is out of the question as everything was disclosed and we should’ve gotten foundation inspection (which we didn’t).

We cannot do repair now – but since soil is so unstable in general in houston area – I wonder if there’s anything I can do to stabilize or even fix the situation by aggressively addressing DRAINAGE? What options would be best ?

I thought of French drain (the one that’s actually goes below the foundation and directs water away from the house) all AROUND THE HOUSE.

Thought to also try to lay a concrete walkway also all around starting right from the foundation with a slope away (about 4ft wide)

I know people here WATERING their foundation in the summer – but what if we get the water away from the house completely with all the drainage to not even allow it to swell?