From personal exp. guess who is not a popular game mode, and zombie survival is one of the worst servers to run it's almost as cancerous as HnS (Hide and Seek), people constantly teaming thus blocking doorways, my suggestion is a bhop or a surf server. TBH both DR and Murder can have a lot of players if there was people trying to get it populated but for me I'd rather play on other DR servers because of the speed cap, most servers have it at capped at 1k, ours is 1/2 of that. A slight increase of it might see players joining, also fixing some timezones (some maps have exploited times i.e only 4 seconds, or doesn't have it at all) and Death areas might help with that as well. Murder I haven't had any interest in it so I can't comment on that.
The smol an frigil coffee addict