On that topic, I recently came across the paper "Scalable Eventually Consistent Counters over Unreliable Networks" [1] which highlights some of
the scalability problems with CRDT counters at large scale: namely the propagation and maintenance of a version vector that keeps growing
over time and requires broadcasts across all members. The paper then describes how some implementors of CRDT counters tackled this limitation
by using "server side only" counters, and the inherent issues with that approach. Finally it proposes an alternative called "Handoff counters" in order to overcome the scalability issue.