Hello @PalisTheGOAT,
Regarding the disconnect issue on the 2.4GHz connection, have you tested for the 2.4GHz wireless interference around you? That could be the reason for the 2.4GHz band disconnecting. You can install a Wi-Fi analyzer to review the 2.4GHz wireless channels around you, then disable the Smart Connect feature on the AX11000 and select the best (least congested) 2.4GHz band channel to test the connectivity again. BTW, you can also change the wireless security to WPA2-PSK AES, then monitor again.
Regarding the reboot issue when rebooting the only computer that is hardwired to the AX11000, please try disabling the QoS and removing the computer from the High Priority to check again if the router still reboots. Can I know the brand and model of the Ethernet adapter on this computer?