I'd like to build a dedicated wifi 6 (or maybe 6E if the project takes long to implement) AP to connect two wireless laptops to a wired NAS. My current AP+router is TP-link TL-XDR3020 AX3000 (Intel Lantiq), it works great but I don't really trust the firmware, and would prefer to separate NAS traffic from other devices e.g. smartphones which also use 5Ghz band, to maximize performance.
Hardware-wise, I'm thinking:
(RK3399) Rock Pi 4B with m.2 pcie x4, because I have one (to be replaced with some RK3588 or RK3568 board with 2x pcie slots, to use second slot for 2.5G ethernet or something else, once hardware options and software support are there);
MT7915 miniPCIe 802.11ax 4x4 adapter (e.g. AW7915-NP1 from AsiaRF);
(powered) m.2 to full-size PCIe adapter + pcie to minipcie adapter, and the whole system powered by PicoPSU with appropriate 12V brick - that way MT7915 should definitely get enough juice;
(XMM7160) EM7345 m.2 USB LTE modem, because I have one, should I ever need LTE for whatever reason
How realistic is getting this thing up and running under OpenWRT?
p.s. please let me know if I'm overthinking it, and should just use the TP-link AP+Router for everything. For reference, NAS uses enforced SMB3 encryption and local-only Syncthing, nothing else, with management over serial console. Still, I'd feel more at peace with a regularly updated open-source solution, and building a DIY AP+router sounds like fun.