This summer, I set up a load-balancing router to have 2 ISPs on one home network to improve my internet connection. I found a cheap TP-Link router on Amazon, plugged in my Comcast and T-Mobile modems, and configured the router to keep one ISP per application and based it on bandwidth. I also set up failover if one connection failed. The internet has been flawless with the load balancing and we have a glut of bandwidth for conferencing, 4K streaming, and security cameras.
A review of T-Mobile 5g Home Internet. A great backup system but not something to be relied upon.
How to dump the CenturyLink provided C3000A router and use your own for better performance and speed when swapping to fiber.