How do I make my MacMini into a load balancing Router

Lol, paid until February, cant leave yet.

Need to work this challenge and maybe with the services already provided in Ios. Problem is testing, with the connection dropping out I cant determine by experiment.

Using iOS and activating cellular, I see 'personal hotspot' when turned on provides 'wifi assist' which is perfect. I connect to the strongest wifi signal and use cellular. Looking at the 'network preferences' panel on the mini running Catalina, I can set the order of the network service. I would place 'iPhone USB' at the top in order to use it first. It provides connectivity from the first wifi and cel service. What does 'disable unless needed' accomplish? Does it provide multi-homing service or just on/off?

https://support.apple.com/en-ca/guide/mac-help/mchl7594e36f/mac is unclear what that does.

https://support.apple.com/en-ca/HT203302 still not clear

Does the network preferences set order allow multi-homing?

This article is unclear, https://support.apple.com/en-us/HT202480 does it see the connection but if there is no data coming will it stay on that connection? That is not useful in cases of bad internet.

What I want for Christmas, Tim Cook please, is a version of "wifi assist" in the Catalina and up 'network preferences' panel that manages multiple internet connections. That is, when an internet speed slows it looks to the next in line network connection for better service when the 'disable unless needed' option is selected.

Thanks, Ken