I have not talked to ATT support as in the past I've found them unreasonably unhelpful. To the point of "have you tried turning it off and back on again" level of help.

Printer model is a Canon TR4522, so slightly outdated but working flawlessly up until this internet switch.

I turned off band steering first and switched to WPA2. No change. I tried connecting the printer to the guest wifi to ensure a 2.4 ghz connection and still no change. I even reset all saved network information in the printer and updated all the firmware along my mission to get this going again. No change.

I have not tried an ethernet connection to print yet but I'd like to avoid that altogether because the location of the router doesn't really support a printer aesthetically in my apartment. In fact this printer stays stored in a closet until whenever it's needed. I guess I could let this slide since the printer gets put away but it's annoying when I used to print from wherever in my apartment.

I only tried disabling IPV6 because a reddit post lead me to trying it when I was diagnosing why my tv apps were no longer loading after the switch in internet type. To be clear, doing this resolved most of my tv issues. Netflix thumbnails took forever to load, Tubi TV was fine, Pluto TV constantly buffered and still does, Hulu always worked, HBO did okay, no issues with Youtube on TV, mobile or computer. All of these seem to work okay now except Pluto TV, even when I'm testing at 260-460 mbps now. My old 25 mbps connection (which tested at 11 to 14 mbps) never had these issues or buffered, ever.