Setting up a learning infrastructure

Hi!

We are running our own custom LMS at the moment. We got a very basic content authoring tool, some very basic reporting and a great UI/UX. In the future we don't want to invest more money in maintenance and development of this LMS because we want to concentrate on content. For content authoring we want to switch to Articulate Storyline and Rise. What I don't understand is how to get these courses to our users. 

What I need is a solution where our users don't see a transition between our platform and the learning platform (API, SSO, full control over UI/UX - not just CSS/colors/logos). Learners should have the possibility to do assessments and collaborate within predefined groups on the course content. Clients should have the possibility to check-in on the learning progress of their employees.

I think we don't need a rich authoring tool on the LMS side, because Rise and Storyline do a great job there. My concerns are the integration in our platform, the reporting and the enterprise readiness of the tools out there (EU GDPR).

At the moment I feel like dancing in the dark with a tiny light at the end of the learning tunnel. Is there anybody out there who serves online training to different enterprise sized companies? How did you solve this issue?

I posted it in Rise. Don't know where this one fits.

Would be great to get some answers.

Best,
Mathias