Merge conflicts arise just as easily in a cloud-first app than in a local-first app once you go beyond any simple "last edit wins" consistency model (and if you have that model, it's also no problem for local-first). What counts as a conflict depends entirely on the data domain in both cases, and that's the hard part.

It's just easier to implement cloud-first because it's just CRUD with a centralized database on a server. It's still extremely hard to reliably connect two apps directly peer to peer without some centralized server as an intermediary and since you need a centralized server anyway and in addition have to do the peer to peer syncing, "local first with syncing" is inherently more complex than just syncing to a master database. But potential merge conflicts are the same in both.