The limit is roughly 130-140, depending upon your system. Please see the tutorials in the ' Mod Managers' section of the wiki ' FNV General Mod Use Advice' article. But you have a number of mods which require one or more of the DLC (none of which are 'active'), which is why you are getting the 'Missing Masters' error. Did you install the DLCs from the Client Library tab? Do you have them included as both 'installed' and 'active' in your Vortex 'profile'? This is a problem with your use of Vortex, not the game itself.