I've read some Apple articles wherein they recommend a value of 3. Can't find the reference. @Lynx we upgraded our devices to 13s and have not experienced the similar issues. Can't help you.
For reference, these settings work well:
config wifi-device 'radio1'
option type 'mac80211'
option path 'xxx'
option channel '149'
option band '5g'
option country 'US'
option cell_density '2'
option beacon_int '101'
option he_bss_color '8'
option he_su_beamformee '1'
option htmode 'HE80'
option txpower '24'
config wifi-iface 'wifinet2'
option device 'radio1'
option mode 'ap'
option network 'lan'
option ssid 'my-ssid-name'
option encryption 'sae-mixed'
option key 'secret'
option dtim_period '3'
option wpa_disable_eapol_key_retries '1'
option ieee80211w '2'