Is there a way to force connecting to the 5Ghz wifi band?

[Bakul Shah]

I have to disable the 2.4Ghz band on the wifi router for my
FreeBSD laptop to connect at 5Ghz. If both bands are enabled,
it always connects at the lower freq (and lower throughput).
I don't see an obvious parameter to set in wifi_supplicant.conf.
I could use a different SSID for each band but wondering why
isn't the higher speed preferred at least by default.

dmesg reports

iwm0: <Intel(R) Dual Band Wireless AC 9260> at device 0.0 on pci3
iwm0: hw rev 0x320, fw ver 34.3125811985.0, address 48:89:e7:81:ab:c3

I am running -current.

Thanks!

Bakul