[api]

Layering independent crypto is safe, otherwise one of the layers has some nasty vulnerability. Security should not depend on the type of traffic. If it does something is wrong.

In fact it’s common practice in high security government use cases to mandate two layers built by two different vendors for defense in depth. That way a nasty bug in one doesn’t compromise anything, and the odds of a nasty exploit in both at once are quite low.

You might be thinking of bespoke combinations of algorithms at the cryptographic construction level where the programmer is trying to be clever. Being clever with crypto is dangerous unless you really know what you are doing.