if you need power, i do not think Tesla is better than anything else. It is just Hype, because it is written Tesla on it.
for the same price of a Tesla wall 1 , you can get twice the power in chinese battery (or half price for same power).
Tesla car batteries are made for a car, so unless you get one salvaged for almost nothing, you get no gain going that way.
Tesla give no support out of a tesla car.
Cheap chinese LFP is about 1500$ for 8 cells at 200A. that makes 5KWh.
to get the equivalent of a Telsa wall 1, you would pay 4500$, while a Telsa wall is about 8000$.
you will need to add a BMS (150$) and some converter/controller (about 600$).