The thing with Owncloud/Nextcloud is the complexity of the system. When many users are working with the files at the same time, there's a lot of messaging going on in the backbone. If people are working in shared folders, that traffic goes visibly up.

Messaging between systems is hard. When things are async, it's harder. When there's async concurrency, it becomes spicy.

I'm managing a Nextcloud instance at the office. Even with this relatively mature state, it can bork itself pretty decently. Also, it has separation of responsibilities and a system admin is not an admin the traditional sense so, a lot of things are hidden between logs and other layers.

Complicating this further by adding microservices is a brave idea at least. We're going to see what's going to happen.

I hope they succeed but it's not a piece of cake.