TX2 WiFi freezes/pauses/lags every 5-10 seconds

I’m running JetPack 4.3:

cat /etc/nv_tegra_release
# R32 (release), REVISION: 3.1, GCID: 18186506, BOARD: t186ref, EABI: aarch64, DATE: Tue Dec 10 07:03:07 UTC 2019

[L4T r32.3.1 == Jetpack 4.3]

I see people have had trouble with WiFi dropping out in previous JetPacks:

Is there a patch available for the bcmdhd driver that will allow 5Ghz and/or solve long data freezes?

If the TX2 doesn’t support 5Ghz WiFi, which USB WiFi dongle works with built-in drivers on TX2 (Linux kernel 4.9-tegra)? (This has some info for old TK1: Jetson/Network Adapters - eLinux.org)

I need one with an external SMA-port antenna, to move away from metal base of robot.
(Quasar Carrier: 2x USB 3.0)

I’ll get this one based on the RTL8812 (AU?) being listed in that TK1 page:

Is there a command to enable 5Ghz mode on the TX2 wlan0?

sudo create_ap -c 36 --no-virt -g 192.168.168.105 -m bridge wlan0 eth0 test testtest
Channel number is greater than 14, assuming 5GHz frequency band
Config dir: /tmp/create_ap.wlan0.conf.KiJsh7UV
PID: 21693
command failed: Input/output error (-5)

ERROR: Your adapter can not transmit to channel 36, frequency band 5GHz.