I found a message from July last year fro you (Roadmap for Circuit Relay v2 File Transfer? - #2 by ylempereur) with the following ipfs config:
ipfs config --json Swarm.RelayClient.Enabled true
ipfs config --json Swarm.EnableHolePunching true
Reading the doc it seems like hole punching is already enabled by default but I just wanted to make sure that are no default ipfs config I could try to play with to increase the success rate here?