This is the exact modpack I am using in my Symbiote Vs Phayriosis Infection series. Some folks asked for the modpack, so, here it is!
The core components of the modpack are ChaosZ Pack, Phayriosis, TaCZ Guns, and of course, Symbiote: A Bonding Experience.
Loot old world ruins for firearms to face off against the horrible monsters that are coming for you, or find a meteorite crashsite for a little extra help...
Remember that if you want cities to generate, during world creation you need to go over to the far right tab, click cities, and click on the preset until it no longer says 'Disabled' and instead says 'aaaaaazflat' (or something along those lines).