tmobile router

Thanks for asking. I'm connected except for my printer, which will only connect to a 2.7G channel, whereas my new iphone is 5G. I'm trying to log in to the router so I can see if the D371 (model FAST 5688W) supports running both channels--my idea is to name the 5g "home router" and the 2.7g "printer" (and give the latter a different password). Then my laptop and phone connect tot he 5g and just this one older printer to the 2.7. I've tried doing this using the tmobile internet app but it only allows me to select one channel or the other.