Not sure there would be a decent enough return on investment, especially if the other tools they regularly use provide more reliable service at no additional cost.

Won't help. I've had multiple callers encounter trouble with what I guess WebRTC traffic due to browser extensions, "anti" virus software, VPN policies etc. Zoom etc. works fine. They usually fixed it by switching to a personal phone instead of a work laptop but in general, the situation is not tenable.