The value of the metals will depend a lot on the battery chemistry. LFP batteries don't need nickel or cobalt and sodium-ion batteries can also replace the expensive copper foil on the anode with cheaper aluminium foil.

I'm somewhat sceptical that used batteries will ever be worth much other than as scrap given the cost and complexity in testing, installing, and managing a mixed set of used batteries in larger installations.

With new batteries halving in price every 4 years or so the value of the raw materials in old NMC batteries alone should make it economical to sell for scrap and buy new batteries for stationary use cases after 10 years or so!

If you ever are looking to implement that EV battery as house backup, this repo might be useful: https://github.com/dalathegreat/Battery-Emulator

I did mine with it and old leaf 24kwh battery (~60k km). After all the safety margins I get ~15 kwh out of the battery.