From issue [[https://github.com/bitcoin/bitcoin/issues/16382 | 16382]]
> When the "maxfeerate" option is not passed, the default fee rate is interpreted as an absolute amount. However, when it is passed, it is interpreted as a fee rate.
This makes the interpretation of the default value consistent with a provided value.
This is a backport of Core PR16521 - part 1 of 2
Commit: https://github.com/bitcoin/bitcoin/pull/16521/commits/261843e4bef96ab296a9775819a99bfa60cad743