Better solution for quick group chat than Firebase real time db?

I built out a simple group chat (rooms with members) using firebase real time database.

What I've built feels brittle because I have 3 client side implementations (web, ios, android) for chat and have to make sure I don't mess up my data structure. I do like the rules and how easy they are to configure.

I've been looking at twilio, and it seems pretty easy to set up chat. What are some good solutions for chat which have SDKs for web, android, and ios? Prefer sticking to something that works out of the box on these platforms (like firebase), and also maybe you have used before.

Thanks!