Launch Team communication platform

I am assembling my first launch team. As of now, because the majority of my pool is from my Facebook followers, I am using Messenger to communicate. As I spread out and glean from other areas, i.e. mailing list, etc, I know that it is going to become more difficult. Someone suggested GroupMe, or What'sAp. I’ve also read Microsoft Teams, but I realize not everyone on my list will have access.

What have some of you found to be easy to access, non-intrusive, and not off-putting as far as me asking some of my people, (many who are in a demographic who may not be very tech-savvy) to download yet another app to their phone, tablet or laptop. *Notice I referenced Facebook and not Instagram or TikTok. wink wink.

Do you create two platforms? Sounds messy….

Appreciate the feedback,