Wait, do you mean a multi-hop vpn, or actually multiple vpns/tunnels used at the same time (maybe you can decide which app uses which or based on AllowedIP like in wireguard)?
They should work with this guy. This software is really great.
https://github.com/celzero/rethink-app
And or somehow have the phones VPN to allow multiple VPNs connected together like in a series. I don't know if that's like possible with a stock android system or even if you root your phone and have Custom firmware that the VPN acts that way or my idea doesn't actually exist. It should exist because it makes sense to me but by stock Android doesn't work that way. The best security is layers of security.