I also doubt that there are miners who changes the default minrelaytxfee line to bitcoin.conf.
There are Bitcoin nodes do customization for their node configurations, but challenge for you is, you don't know where are these nodes and their IP addresses.
They can customize their node configuration like this.
https://jlopp.github.io/bitcoin-core-config-generator/They can customize this parameter
Min Transaction Relay Fee
Fee rates (in BTC/kB) smaller than this are considered zero fee for relaying, mining and transaction creation.