The upswing for the vanilla mace should be entirely removed. It should behave the same way it does in vanilla. The current default BC behavior is very broken and makes the mace practically useless. This has been mentioned in an issue already (#496), except for some reason, it was just closed without any actual proper resolution, nor an easy configuration option, just an answer that is equivalent to "do it yourself". Just because people can change it themselves by making some datapack doesn't mean they want to, and it doesn't mean the default shouldn't get changed.

The tolerance between starting a mace swing, falling down a long distance and actually hitting a target is extremely slim with BetterCombat, and especially combined with high network latency (ping), it is impossible to actually use, making it pretty much a useless weapon. Hitting a target should be instant, just like how it is in vanilla. The way the mace works is very, very different from any other vanilla weapon, and therefore should be treated differently in this combat system too.