I had a similar issue. THis post should help:
After I renamed the mod list, I was able to get to the main menu. After that, it was a process of adding the mods back, one at a time. If I was able to get to the menu, I’d launch a single player game to ensure I could get into the game.
After several cycles of this, I determined that half of my mods were causing the game to crash. Since then, four of the mods I had to disable have received updates for Siptah.
Hope that helps.