And if so, what interfaces can connect to them, and how do they do that?
I want to analyze with Lc0, but I don't have a computer with a GPU; I could rent one for a short time period at various cloud providers, but then I don't know what GUI I could use to talk to an engine running somewhere on the Internet.
Do e.g. Chessbase, Scid, Aquarium etc have a feature to work with engines running in the cloud?
Chessbase has this feature for subscribers. Basically you can analyse your games using their cloud based engine. If you have a powerful machine yourself you can also "rent out" your engine. More details here.
Here is an older article which includes a video explaining how it works and walks you through the process.
Next Chess Move offers a number of engines in the cloud including LC0, although they charge a subscription fee for access to more powerful hardware.
At the time of writing, they provide an app on Android and iOS, though it doesn't appear to have any integration with desktop programs.
