That certainly _used_ to be the case, but it looks like 802.11ac is supported in iwlwifi since FreeBSD 14.3: https://man.freebsd.org/cgi/man.cgi?query=iwlwifi&sektion=4&...
And it looks like they're adding 802.11ac support to some realtek drivers too: https://www.freebsd.org/status/report-2025-10-2025-12/#_linu...
Not to sound like goal post mover, but once you tried 802.11be @ 6GHz, you never go back (assuming what your AP connected to can handle it).
That's my problem with FreeBSD on non-servers - eventually it's supported, usually via Linux shim, but it's too late. By the time FreeBSD started to support (on CURRENT) GPU that forced me to switch, I already upgraded twice.
Glad it's getting better.