Meritez’s solution is good, I was thinking of the usual network where everything is administered by DHCP and forgot about the option of static config. Meritez’s solution as is however will never work for all your IPv6 traffic, which web browsers default to, so the majority of your traffic could be ignoring your setup. You would need to see if you could get static IPv6 config set up similarly.
Why don’t you just bond the two together? Because you’re not on all-you-can-eat 5G and it would guzzle 5G data allowance?