A sports group of my local sports club unofficially uses a Whatsapp group. This group is used in particular for announcements (eg changed meeting place, etc.). At the moment I find it unrealistic to migrate all participants to another system. However, it might be conceivable, at least for announcements, to open a second channel so that those who cannot use Whatsapp are not completely excluded.
Is there any experience on this topic? Is there possibly a Whatsapp crosspost software to another channel?
I experiences similar challenges in the past and didn’t really found a solution. Matrix has a WhatsApp bridge, but it seems to be quite complicated to set it up. As far as I understood it you need to run a Android emulator in a VM with WhatsApp. Then you need a WhatsApp account which is configured in WhatsApp running in the emulator with which you join the group and then the bridge can cross-post stuff into a Matrix room: https://matrix.org/docs/projects/bridge/mautrix-whatsapp/
Since I am primarily concerned with the announcements (eg date shifts), it wouldn’t be necessary to have a bridge for the entire Whatsapp group. It would be enough (for now?) if announcements were published on a second channel. Since this is not protected information the publication on a website (blog?) or a service like Mastodon would be conceivable. It would be nice if we had success stories to learn from…
Have you tried asking?
Is there somebody responsible for coordinating the announcements? Then perhaps that person can inform you via a separate channel. Building some goodwill will help: explaining that you choose not to use WhatsApp and you’d appreciate it if you are contacted via a different channel. Perhaps you can agree on a channel that fits you both, like email, Telegram, Signal, Matrix/Riot, XMPP, SMS, etc.
Or if there is no person soley responsible, hopefully one is willing to help you out.
I believe asking somebody in person will have a greater change for success than making it a problem of the group.