Internet speed from certain device regresses several times a week until gateway is rebooted

My issue is pretty much exactly as described in this post: https://forums.xfinity.com/conversations/your-home-network/how-often-do-you-have-to-restart-your-xfinity-gateway/65babafd56dae762b6880ba3.

Basically, several times a week my internet speed will be noticeably slower on my laptop only (speed < 25Mbps) and then I'll reboot my gateway and I'll be good (~50Mbps <= speed <= ~100Mbps) for usually anywhere from a day to a few days. Sometimes the speed regresses within hours. During the slow down periods I do notice that the "connection type" in GeForce NOW shows that I am connected to my gateway on the 2.4GHz band rather than 5GHz (and then once I reboot the gateway and reconnect I'm usually back on the 5.0GHz connection thereafter)... but I have no control over this as I only have the 1 home network, not distinct networks under "2.4" and "5.0" suffixed SSIDs.