Welcome, I Recommend Using Tissou's Zombie Pack For A Better Experince, Along with SEUS Renewed.
The Modpack is fully configurable
You need to go to your config file on your pc (on the server files if you want it multiplayer)
You Can Change:
InControl: Zombie Spawnrate.
DayZombies: Zombies Strength, Speed, Health, During Day Spawnrate.
EnhancedAI: Make Zombies More Smart; They break blocks, They Use Enderpearls, Try to lure you with a Fishing Rod.
ZombieAwarness: It will make zombies detect you in the light, detect your sound, and smell your blood when damaged.
TheHordes: Spawns Multiple Zombies at once, with a chance of infection
BadMobs: Control Which Mobs Allowed to spawn (remove spiders, skeletons, phantoms, creepers, endermen).
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Also You Can Config The files from a server and not for everyone, and it will work for who ever joins, you don't have to make them change it from their files too (Config Server-Client Support)
Have fun.. You Can Use Any Map You'd Like, And It will work just fine.
(Also Zombies will chase you, break down doors, will do their best to get you.. they are really smart... SO THEY WILL FIND YOU WHEREVER YOU HIDE. Fight Back Instead!)