I have the following in my
bitcoin.conf file:
# Fee rate (in BTC/kB) used to define cost of relay, used for mempool limiting and BIP 125 replacement.
incrementalrelayfee=0.000001
# Fee rates (in BTC/kB) smaller than this are considered zero fee for transaction creation
mintxfee=0.000001
# Fee rates (in BTC/kB) smaller than this are considered zero fee for relaying, mining and transaction creation.
minrelaytxfee=0.000001
(Source of comments to the options from
https://jlopp.github.io/bitcoin-core-config-generator/)
Can't say to be confident if all three are actually needed. I thought, why not pick anything that's remotely about fees.

Eager to learn more...