I hugely support the idea (or just using Debian), but what a sad sad sad sad sad state of affairs there is with trying to do this!
There's the most limited, tiny, miniscule amount of wifi add-on cards one can buy with decent chipsets. Consumer offerings with consumer-targetting chips have never worked well for me (terrible performance with multiple clients, huge multi-second drop outs, low max client limits), and I spent years trying hard to make something work. The market feels basically reduced to one company, Compex, making PCIe & m.2 addons[1] one can maybe perhaps buy, that do a decent job, and their availability is somewhat scarce, and prices are pretty high.
Imo DIY ought be such a commonsense straightforward alternative to these fancy routers. Alas it seems almost impossible to do, short of scrounging for some expensive, demanding Compex chips, and hoping the open source drivers are up to snuff (they're not always). And Compex prices have gone up and up and up. Their modern 4x4 m.2 card is $400[2], but hey, at least it's possible to buy something: without this card, we'd have nothing. Oh, and that card doesn't have x86 drivers available for it, only drivers for Qualcomm platforms.
[1] https://compex.com.sg/wifi-module/
[2] https://www.arrow.com/en/products/pn02.7/compex-systems-pte-...