hi @Alloy202 , i've uploaded both my General and Professional settings page. See if setting the same configs will solve your issue, else i'm not sure what could be dropping Backhaul from 5 Ghz to 2.4 Ghz...
i had a similar case and this issue was finally solved by turning off the APSD (automatic power save delivery), see my Professional config screenshot below. Now my AIMesh Node has been running on 5GHz uplink for 3 days without reboot.