I think that there are some ways to ensure combat in the server is mainly using Epic Fight by making the cooldown of weapon swings while not in combat mode be a little longer, less damage, and/or less range.

I've encountered that there are still some perks to the modern combat system that are used by players in my server that changes the entire meta of fighting back to the typical system, and on servers with a focus of pvp around the mod, it's nice when everyone is using the same thing so it's less gimmicky.

Also a config to make the default starting mode. Then again integration of the build/fight mode would be dope, but understandably difficult. Even big games like Fortnite or No man's sky require you to go into build mode, so I think its perfectly fine as is. But the build mode tends to be the secondary to the main combat modes.