It all depends on the device, and what OS it is running, and the UI it is offering to interact with the OS and other functionality of the device. Your mentioning of tc, and your device being an Asus one suggests it might be running some Linux with CLI access, e.g., OpenWrt or DD-WRT.
If that is true, this thread has a good discussion of potential options, including tuning the connection tracking system a bit if it cannot be disabled entirely.
Note though that while a very common issue, device performance seems not the primary issue in the case that triggered this current thread.
Rather, as far as I understood, that the high traffic volume/bitrate was triggering DDoS protection mechanisms on the cloud provider side, and generally exceeding the contracted bandwidth by far, which both in turn would then impact other services as well.
But infrastructure performance (like in this case of what I understood to be a cloud-based instance), or device performance (in a physical setup like yours seems to be) would be likely next potential bottlenecks.