I have connection to local ISP that's good enough for browsing and I pay flat rate. I also have LTE modem that I pay per the GB. All routed by microtiks. The ISP is no good for video or voip calls (jitter, latency) while the LTE does it without problems.
At the moment when I need to do video call I'd switch the default gateway from the ISP to the LTE. Once the call is over, revert back to the ISP. I could make that bit more intelligent and assign proper gateway to the different devices, based on their use (e.g. work laptop / reading ipad) but I'm wondering if anyone managed to do this based on protocol and/or port numbers.
Problem is many tools are used for videocalls — fb messenger, whatsapp, then all sort of corp biz tools — zoom, ms teams, etc. and I haven't managed to build proper mangle tools to identify them correctly.