WikidataCon 2021 was in October 2021, and one of the sessions that I spoke in was a “Pre-launch Announcement and Preview of Wikibase.Cloud”.
The recording is now up on YouTube, and below you’ll find a write-up summary of what was said.
You can also find:
So what is wikibase.cloud?

It’s a new platform that has yet to be launched, that is based on WBStack code, but that will be managed and maintained by Wikimedia Deutschland (or Wikimedia Germany).
This is a Wikibase as a service platform, that exists to offer open knowledge projects a new way to create their own Wikibase very quickly and very easily.