Sounds like my day job of the last 10 years or so.

Although I'm mostly focused on the app code, I spent about four months this year debugging various wifi stacks (one for each generation of product). Only to have most of the problems fixed by moving all products to a 5.7 kernel base. Which was no easy project in itself, but mostly not my work.

In my experience, the processor, memory, flash, and all other things combined are trivial compared to getting reliable wifi.