Frequencies cast upon a mind by an external actor can make you brlieve or do things you don't want to do?

Hmmm. Where to begin...

No.

Zero evidence, open to experimentation and falsifiability.

The obvious: why hasn't the enemy used this on us already? if we know of the premise, wouldn't they?

You want to atrengthen your mind?

Practice Zazen and Shikantanza.

If you believe everything that fits your desired outcome, you can be controlked - NO EXTERNAL FREQUENCIES REQUIRED.