You’ll still have Instagram! Don’t think of it as handing over your private communication to your phone carrier, think of it as “also having that choice”. It ps a step forward to have more choices.

I’m somewhat hopeful, since mobile carriers are somewhat regulated. They can be forced to care. Meanwhile, something like Instagram is a private company with noe oversight, who can choose to do almost anything they think will bring in more money

I trust my data with my ISP farrrrrr more than I do meta, and also I'm very unconvinced my ISP has access to anything at all here.