Is there such thing as a OnePlus "ecosystem"?

Given there's a lot of early bird purchasers here that now have a watch or buds and are talking about going "all in" on the OnePlus ecosystem.

My question is: is there actually an ecosystem to get into, or are there just a bunch of OnePlus devices that you can buy?

Are there any advantages to using OnePlus buds with an OP phone? Does the watch get a better experience? Can you handoff between phone and tablet? Do you get features that are in the walled garden like Apple or Samsung?

Or is just Android and if you install the apps, you will get the same experience regardless of the phone?