Is there a MultiSite Alternative?

I’m using Mulitsite, but each update is a panic attack.
Will it update without breaking? Will the themes work? will I need to start over again?

I need to assign each user 1 page and a category.
The page and category need to use a specific sidebar and all the posts in that category need to use a specific category theme.

Yes, I know it sounds like using Multisite would be easier, but it just falls apart so easily there Must Be an alternative plugin out there.

Please help. What alternatives are there for MultiSite?
Thank you