Obtaining full support for 802.11AC hardware is possible in 2021. The issue is that the firmware code to support 5 and 10 MHz channel widths is not available until Oct 2021 timeframe. This code does exist in the upstream opensource community. However, the developers that created this code are licensing it out to cover their costs and lively hood. Then, in Oct 2021, we have been told, this code will release to openwrt and become available for AREDN's use. Until then, only 20MHz channel widths could be added to the AREDN firmware.
Regards,
Joe AE6XE