GL.iNet is more open (they run an OpenWRT fork that they open source with a proprietary GUI on top). They have a beta for a mesh system on top of that: https://www.gl-inet.com/en-us/pages/mesh . I haven't tried the mesh, but I have had very good experiences with a few of their routers and they are what I recommend to friends.

Ubiquiti mesh stuff works very well and is an overall polished experience. Supposedly their APs are at least distantly descended from OpenWRT but they are not open source. Their platform is pretty open in terms of integrating with other stuff and not locking you in, at least.