Best load balancing mode for double WAN 4G + VDSL
I would like to ask for the recommended configuration of load balancing for the following situation:
I have a cable internet connection with 1Mbps Upload that works fine for navigation and low-quality video calls but can't afford to upload "big" files. Basically, the file upload takes almost all of the bandwidth and the rest of the connections get very slow or even block, so I have to give up.
I would like to add an extra 4G internet connection + load balancing to help in those situations the upload bandwidth of the cable WAN gets saturated.
In this case, should I configure the 4G as a backup/failure connection? Or, if I set it as a backup, then the router won't use it unless the cable WAN is completely down?
How could I set up the two connections to prioritize the cable one first?
Of course, any other suggestion to solve my problem is welcome.
Thank you so much for your help!