Just putting this here in-case someone has the same problem I did. I had a very similar issue where the server console would stick at "Loading fastfile seasonpass_load_zm" and I found the problem to be with my "dedicated_zm.cfg" in Plutonium's AppData location.
Within my config under the map rotation section at the very bottom, in copying and pasting different maps I had accidentally omitted the "sv_maprotation" and just left the "exec zm_[whatever_map].cfg map zm_[whatever_map]" command. In adding back "sv_maprotation" before the "exec" command, the issue was resolved and the server began to function normally.