IIRC Ozzmosis was a mish-mash of three different unfinished projects. There was the No More Tears sequel with Zakk, the Steve Vai project and then another album with a bunch of outside writers. The final album pulled stuff from all of those writing sessions.
In hindsight Ozzmosis was definitely the turning point. First six solo albums were band efforts. Down to Earth was all outside writers. Zakk wrote on Black Rain but Black Rain and Scream are defined much more by Kevin Churko than Zakk or Gus G. Same with the Andrew Watt albums. Ozzmosis stradles both eras.