Even if it wasn't connected to a surfboard (assuming the OnHub was also capable of being a modem), you would then need to route a coax cable to the middle of the room. There's 0 reason to keep the surfboard physically close to the AP, and IMO, it's preferable to not keep it close (because that way I can keep my network switch near the modem instead hidden behind all my electronics never to be seen). Either way, you will be routing a cable to the center of the room, you're just deciding whether you're routing a coax cable or an ethernet cable.
Even if it wasn't connected to a surfboard (assuming the OnHub was also capable of being a modem), you would then need to route a coax cable to the middle of the room. There's 0 reason to keep the surfboard physically close to the AP, and IMO, it's preferable to not keep it close (because that way I can keep my network switch near the modem instead hidden behind all my electronics never to be seen). Either way, you will be routing a cable to the center of the room, you're just deciding whether you're routing a coax cable or an ethernet cable.