I don't have a large friend group, but got most of them to switch after I left Facebook. I just don't tell people I have WA and only use it if I'm forced to. You might have better luck since Signal has improved a lot in the last 6 months and there is a good desktop app. But you might need better friends. Friends that might warn you about how your username suggests you're a Nazi (I assume this is unintentional and just your birthday year)[0]

[0] https://www.urbandictionary.com/define.php?term=88