How to convince my friends to use signal

I wish they would use whattsapp, rather than getting me to talk about sensitive and highly personal information in unencrypted channels. The obvious solution is to limit what I talk about for those who won’t switch, but it seems I’m not that responsible, especially if it means losing contact with someone important to me. I did have someone get me to start using signal this way back in the day, though. Before that, she would make vaguely supportive statements, but not share any personal info or opinions. When I asked why she was acting this way, she said that from a safety perspective she was only comfortable sharing that information on signal. I couldn’t really argue with that and eventually figured out how signal worked to stay in contact with her. In your situation, I think I would get a separate device (pixel 9a grapheneos?), use it for whattsapp only over WiFi with a VPN, and check for messenges once per day or once per week. This will limit telemetry somewhat and the messenges themselves should be encrypted. If people ask why you are slow to respond, you can explain you use a separate device for whattsapp due to not feeling safe having whattsapp on your main device due to meta’s tracking. Then on their own either they accept a slower response or move to Signal, without you coming across as controlling or critical.