Only a max of 30 zombies are spawning regardless of my settings in the world menu and commands, i've deleted the whole game, the regedit, the app data folder ect
Best guess, your gamestage or other limiting factors are holding the number back. Can't say for sure without all of the details though, which will exist in that log.
The way the blood moon zombie count works has changed in V1.2 for better performance. The zombie count now caps at 30 and scales up the game stage based on what you have the blood moon zombie count option set to. The line below is from the V1.2 b27 Stable announcement post.
Blood moon party maximum active enemy count with increased game stage scaling based on the full count