I really don't know what happened but lately I noticed a decrease in internet speed via Wifi. This was confirmed when I did a simultaneous speedtest via LAN and Wifi. I am getting over 100Mbps via LAN

My home network mainly consists of the ER605 load balancing router where I connect a Fiber internet connection and a backup LTE modem. To have WiFi I connected an Archer C64 operating as an access poi

I recently added a wired internet connection to my ER605 and made it my main WAN, leaving my cellular LTE modem as a backup. I've set up the Link Backup so that If my main WAN fails, the LTE kicks in.