Working remotely doesn't mean you're not connected with your co-workers :) We don't have to be next to each other to have good relationships. It takes time and some practice to establish this sort of culture. If you have team meetings which are purely for brainstorming and connecting, these barriers are taken down easily.
Also, if you have pure fun slack channels that helps too. E.g. The whole team can share what's been going on in their life and fun stuff they found on the web. Also, our standups are not all about work, we check how each other is doing and support each other.
If people truly care about each other, kilometers don't count. There are 6,480 km between me and the rest of my team, but we all get along really well. Of course, we do plan to have a team gathering once a year to meet each other in person :)