Depending on your speed, you may need a bit more than just a decent router. Many routers can't hardware accelerate qos traffic, which will be needed to limit the speed.
My Netgear R7000 can't handle my 400mbps connection using qos throttling. I will need probably at least a mid range Ubiquiti router to handle it.
Ubiquiti routers won't help you; they're even more reliant on hardware acceleration than typical consumer brands, and nobody has put the best modern AQM algorithms into silicon yet. What you really need is a CPU fast enough to perform traffic shaping and AQM in software, which ironically means x86 and Intel are the safest choices.
My Netgear R7000 can't handle my 400mbps connection using qos throttling. I will need probably at least a mid range Ubiquiti router to handle it.