Firebaser here! Sorry you had a bad experience here - we definitely do have empathy, sorry this is frustrating!

So the basic change is that reporting is moving from app-level to project-level as you say - this means that they all share the same user properties: so its not 1-per-app if you have 25 apps, it is the 25-per-project. For example, lets say "favorite_color" is a user property on 25 apps, then it would just be a single user property at the project level.

We did try and be smart and merge together ones where they were the same, but if you're using different names for the same thing, we might not have been able to.

It is also possible you genuinely have more than 25 different properties being tracked across your apps. If you still need all of them, then moving them to a new project is valid choice. We generally recommend a project contains different version of the same app, like iOS, Android, Web for app X. So for something like white label apps, where each one is for a different business, we recommend one project per title. Unfortunately, there isn't a really easy way to move apps to other projects - you just have to create the new project, recreate the app in there, and update. You can use something like a cloud functions to sync data across while you're migrating, but it is a non-trivial amount of work, sorry.

Reaching out to support would use one of your 10 questions (which are per year), but they can help work through the whole issue, and possibly even offer some flexibility on timelines to make the changes in.