I don’t disagree but don’t let perfection get in the way of good enough. SMS and standard email etc are all unencrypted. WhatsApp is encrypted end to end. You may not trust meta, or like them. But that’s millions time better than SMS or email.
Getting your parents on WhatsApp is a huge awesome step. Getting them to telegram or Signal or whatever else is a minor step comparatively.
Seconding. I have a 3D printer. A couple of them. And I use JLC for PCBs and 3D prints because they have AWESOME printers and it’s just as fast to push the button and have it show up from them as it is for me to find the time and baby a print.