You can try to connect to each SAAS platform from one dashboard app through API connections (provided that those SAAS platforms offer access to user data through API calls)

Yes, there's six common ways teams integrate their data to build a single view of the customer: https://www.hull.io/blog/customer-data-integration/

1. One-click native integrations
2. Manual CSV export --> spreadsheet --> import
3. Dozens of if-this-then-that workflow tools
4. All-in-one platforms (for every team in your company)
5. Custom scripts between APIs
6. Data warehousing

But what you're really describing is Hull - "One customer profile to power them all" :)

Precisely because teams have so many tools with lead and customer data across the entire customer lifecycle, you need some way to combine that data, clean it up, enrich it, and sync it across all your tools.

Hull's a customer data platform for B2B SaaS companies to do exactly that in real-time: https://www.hull.io/

The term "user data" is pretty broad, can you share more specifically what you're looking to collate into a single view?

I work for a company called Databox. Our application allows users to pull data from 50+ different sources (including the 3 you mentioned) into single-view dashboards. Again, not sure if this is exactly what you're looking for given your description, but wanted to get it in front of you in case it can help.

Check it out here: https://databox.com/

If you have any questions, let me know : )