For Slack at least you have the option to change that back to use Enter for new line (which is what I do), but other software is not that generous. I think Grafana introduced yet another way, Shift-Enter to submit, that I alway mix up.

Hot take — Shift enter to submit should be illegal everywhere. If there's any key chord to submit, it should be Ctrl Enter.

I think I'd be OK with some inconsistency in how Enter works as long as the key chords are consistent!