I would need more details related to what data exactly you need (meta-data, rollups, literally looking at 400million rows etc).
with something like this, I would initially think the following
1. data lake + power bi + dashboard/reports + Embed in Dynamics
2. cosmo's + jobs to summarize + whatever metadata you need + the rollup data values as a Virtual Table
3. Azure SQL database (but... for me I don't believe these items are Transactional so you should NOT store them in SQL, but I am adding this)
4. DataBricks + Frabric
This really would be more of a bigger consulting discussion. trust me when I say, its not easy to build a massive scale, high input, reprocessing (constantly) engine just with the data above.
Understanding Access Patterns
Volume / Velocity of incoming data
Volume / Velocity of Processing of the data
Volume / Velocity of access the data (# of users) reports etc
This isn't an IoT system exactly but I would expect that the data comes in, needs to be indexed (this is a general term of organizing), then the data that needs to be visible to the users, ETL, Governance, Obfuscation, you name it.
Now you need to talk about Row level, column level /field level security etc.