Lmao, but I’ve found it’s less about being cool and more about being firm. I’ve got three friends that I told very plainly “I will no longer be reachable via SMS, please use Signal”. Bear in mind that 1) these are people who love me a lot, more like family than friends, and 2) I didn’t try to shame them or demand they stop using SMS entirely. I just said “this is how you reach me now”. All three installed Signal, and one of them now uses it as their primary method of text communication like I do.

Not saying it’s easy necessarily, and I doubt this method would work for acquaintances rather than family or close friends. But every little helps, and it’s a place to start.