Is it possible?
Maybe it is, but it feels like buying an electric car, replacing the batteries with a tank and the electric motor with a gasoline one. Then you realize you need the transmission, then you need better brakes, then…
At the end you have a patchwork, you miss the flexibility of your Django apps on the front end and the convenience of using Anvil and all its magic.
My opinion is that if you want power and flexibility, you should go the Django way, manage your own database, server, security, the whole stack. If your target is working in an environment secure, easy to use, with higher productivity and you are OK with sacrificing some flexibility, then Anvil is the right tool.
If you hit a roadblock with Anvil, for example if you want to use your own database, then you replace the database. This works, has been done many times, I’ve seen people talking about similar configurations here in the forum.
But using Anvil only for the front end feels wrong. I haven’t tried, maybe it’s possible, but…