Why is there CU usage while no activity running?

Just finding out that Fabric runs a load of background processes (One Lake Indexing etc) even when the CUs aren't being actively used. Apparently, the admin has no control over this and the only way to ascertain what's going on is by poring over the inaccurate and misleading data in the frankly crappy metrics app.

I've just experienced an hour of downtime on my production reports because of this even though I'm well within my SKU limits for the actual operations I'm performing.

Looks like we've been missold again with Fabric. Sounded so good too:

As per copilot's comments, you as an admin have to proactively come up with strategies to get around this whilst fumbling about in the dark because Microsoft actively hide this sort of detail from their customers.