This is possible in theory, but will have several limitations.
First. regarding Azure Front door:
You can put any Public IP here, which means you cannot directly point to the internal IP if your on-prem servers and have it direct over your VPN.
You can put another device in between, such as a Load Balancer, Application Gateway, or other NVA which can direct the traffic on-prem.
Before you start down that path, Azure Front Door is designed to be a global entry point. Even if you did have traffic go to Front Door -> Datacenter -> VPN -> On-Prem, it would have a LOT of unnecessary latency.
You can have on-prem backends exposed via an IP on-prem, and have Azure Front Door direct traffic to both Azure via the public ip and your on-prem via your ISP IP. This results in the lowest latency for each server.