@NFtoBC traffic shaping would definitely be a good option. I guess it comes down to cost for a network switch with that capability and how bad they want to control it on their end vs getting a second line and having peace of mind.
The challenge you may run in to is a limitation of the billing system. You won't be able to have 2 residential services active at the same address. If you can designate one as a basement suite then it will go in fine but the system will say there is ...
Keep in mind WiFi signal bars don't really mean anything. If you are getting good speeds that's all that matters when it comes to the quality of the service. Technicians are able to enter homes again now for short periods of time. If you need one to ...
After a bit of googling it does look like that Asus model does support Multicast which is required for Optik TV to function properly. The one thing you'll need to be aware of is if you have any wireless Optik TV boxes they will need to be reconnected...