They should also signal your counterparty's security posture.

Basically, give you a heads up that the other side has settings that make the system less secure.

The default should be "No name or content".

No it shouldn't. That makes the UX much worse, just to guard against the 0.00001% case where the FBI seizes your iPhone.

Not really, that would discourage use by normies.

users should switch to simpleX