Recommend reading the release notes Release v0.11.0 路 ipfs/go-ipfs 路 GitHub which has the relevant information about the recent changes to relay v1 (i.e. unlimited relaying of your data) within go-ipfs. In particular go-ipfs cannot act as a relay v1 server anymore and there is a separate binary you should run for that.
As mentioned in the release notes there鈥檚 a standalone relay daemon at GitHub - libp2p/go-libp2p-relay-daemon: A standalone libp2p circuit relay daemon providing relay service for versions v1 and v2 of the protocol.. I don鈥檛 think it has support for private swarm keys, but if not you could submit a PR to modify the config to take your key and pass it into the libp2p host, it should be relatively simple to do so.