Didn’t Google and such have access to much more training data than open source solutions? I would think that would give them an advantage, unless it’s the raw algorithms that are better.

Both, yealink for physical phones. Ground wire for mobile app. You could always sign up for a test number before you port yours over.

Voip.ms is great, been using them for businesses for years. It’s dirt cheap - probably cost you like $3/month.

I switched years ago to this app to transfer for wirelessly, I get better speeds than usb. Uses your local wifi or internet. https://play.google.com/store/apps/details?id=com.resilio.sync