Try anything that's well-supported by OpenWRT. Even if you don't need support for AP mode, using a chip+driver pair that meets that standard (i.e. has mature AP mode support from an open-source driver that works on multiple architectures) usually means the client mode is also fully-supported (though maybe not Bluetooth). For 802.11ac, that generally means Qualcomm-Atheros ath10k or Mediately mt76 devices, with the latter being more popular among OEMs for use in client devices.
Is there anything that's current and supported by OpenWRT? Whilst I love OpenWRT, it's support is more on the level of it works enough to tx/rx packets and not necessarily all of the hardware functionality is enabled and works as per the specification.
"All of the hardware functionality is enabled and works as per the specification" is a pretty high bar even for proprietary drivers, especially when the hardware has just hit the market.
I think there are now a few hardware platforms capable of using the new 6GHz band channels ("WiFi 6E") on OpenWRT, but I haven't checked recently and haven't been looking to upgrade any of my hardware to support that (I'm doing just fine using 5GHz DFS channels that nobody else in my apartment building is using).
I'm not sure what hardware capabilities you think are poorly supported by OpenWRT or the open-source drivers for the known-good hardware choices from the QCA lineage or Mediatek's mt76 family. Can you provide any specifics?
> I'm not sure what hardware capabilities you think are poorly supported by OpenWRT or the open-source drivers for the known-good hardware choices from the QCA lineage or Mediatek's mt76 family. Can you provide any specifics?
I can't speak for them, but I've used OpenWRT on routers with Broadcom chipsets, so I think they were saying that OpenWRT support isn't a good litmus test for drivers that support the full functionality of the hardware they're for.
I specifically said "well-supported by OpenWRT", because even the most cursory investigation of what hardware works well with OpenWRT will warn you away from buying Broadcom.