If you can get it to run on arm64, and you can manage to provision an instance (they are in seemingly perpetually limited supply), evil Oracle actually has a pretty generous always free tier Ampere offering. You can have up to 4c/24GB instance for free, sliced and diced as you see fit (4 1c instances, for example). You only get 200GB of block storage, though, so you'd have to either pony up for that or use object storage (not sure if nextcloud can use S3-like API object storage).