As @hnyman notes, there have been recent developments on the mvebu platform, and while I have found good stability on my WRT1900ACS with WPA3 and 5Ghz running recent Snapshot builds, I have returned to my usual scenario of running it ‘wired’ only combined with an AP for wifi.
Despite their age and their endemic wifi issues these are still robust and powerful platforms, with useful life for the foreseeable future on OpenWrt.
There is also a well regarded Community Build dedicated to this platform running main/master builds typically updated at least bi-monthly that can be found here: