4G / 5G backup

Hello I am looking for a CPE product that can use the 4G and soon 5G cell network as backup to our fiber. The product should create a VPN back to our network, so the customer can keep his IPv4/IPv6 address and all other services running as normal except maybe at a lower speed. I imagine this CPE router could use BGP to announce itself through both the fiber and the cell backup. Are somebody doing this and what can you recommend? Thanks Baldur