This is the way. I spent a fair bit of time on using cheap chinese SoCs networked on a pcb. At one point you could get 32bit arms with 512mb of ram and 10/100 eth phys for like $.50 in bulk, that can run linux (not easily) (allwinner). But it would take an aweful lot of those to match the performance of an i7. And 32 vs 64bit is a problem.

The "gang of arms" lives on though in Ampere and graviton2 and the like.

Not knowing what the workload is, it's hard to beat consumer gpus for performance and price.