This mod edits the behavior of the countdown timer on the multiplayer lobby ready-check to wait for all players to ready up, then counts down from 5 before starting. As far as I can tell, only the host should need this installed for it to work. There ain't much to it, this is just a small QoL tweak that's bothered me for a while.
Feel free to let me know if this works for you. I'm on Discord as SeahorseJerky#8724 and on the modding server, so shoot me a DM if it's busted.
1.0.0
1.0.1