Failure to establish and/or hold WIFI WPA3/SAE RSN-IBSS VHT connection to small 5Ghz mesh

### I ran into trouble extending my existing Batman Mesh with several new Wifi devices. * The existing configuration worked fine for years on the existing devices. * All relevant systems (now) run up2date 5.x kernels (Debian10.X+bpo, OpenWRT master). ### Wifi connection stup specifics: * WPA3/SAE CCMP is currently showing as "negotiated" for the existing IBSS mesh partners. * Currently participating Wifi chipsets: * QCA9880 (ath10k, Archer C7s/OpenWRT) - Work great, Sub-MS latency, ~600-1100 MBit negotiated. * IPQ4028 (ath10k, B1300/OpenWRT) - connects reliably, but has higher latency than ^ (+~1.5ms). ### Things I'm aware of: * The wanted connection type, IBSS (f.k.a. Adhoc), limits me to 7 per "cell"/frequency. * The other "mesh" type, 802.11s (my first choice), is supported even less well by devices/drivers. Here's the working configuration for wpa-supplicant for the existing 4 devices:

ap_scan=2
country=LU
passive_scan=1
network={
        scan_ssid=0
        ssid="MYSSID"
        key_mgmt=WPA-PSK WPA-PSK-SHA256 SAE
        mode=1
        fixed_freq=1
        frequency=5200
        ht40=1
        vht=1
        max_oper_chwidth=1
        psk="The correct passphrase"
        proto=RSN
        ieee80211w=1
        bssid=aa:Sa:me:For:Al:ll
        beacon_int=5000
}

(I know, the target systems have all prerequsites, because I can make this config work with an old USB stick on both) ### The problematic new devices/combinations are: * Amd Jaguar with miniPCI QCA9377 (ath10k) - fails to connect to IBSS * Intel i5 with miniPCI 3160 Wifi (iwlwifi) - fails to connect to IBSS * Both of the above with Various USB Adapters: * Mediatek mt76x2u, 0e8d:7612, ASIC:76120044, ROM: 20141115060606a, FW:201507311614 * connects __fine__, __very__ low latency, **crashes host hard** soon. * Ralink MT7610U (Archer T2U) mt76x0u, 148f:761a, ASIC 76100002, EEPROM ver:02 fae:01 * connects __fine__, __very__ low latency, **crashes host hard** soon. * Realtek RTL88x2bu AC1200 Techkey, [88x2bu(dkms)](https://github.com/morrownr/88x2bu) 0bda:b812 * fails to connect to IBSS Originally I started with the QCA9377 in the AMD rig, and this is the main reason for this Question, but while testing/diagnosing I got the above results with the other cards/systems, and would like to now also know, how to get them to join a VHT RSN-IBSS network. Notes: * I can post more details, and will edit in requested command output. * Mesh Conf is fairly standard for a batman L2 mesh using several wired/wireless link( type)s. * The links are backhaul links, they transport BATMAN ethertype encapsulating several L2 VLANs. * To transport MTU1500 w/o fragmentation, the phy links __must__ run at MTU 1560+ * The current Mesh participants run at MTU 2304, the WIFI maximum. (Ready to compromise on that) * All of the above wifi adapters list IBSS with RSN in the iw phy output