Seems unconstitutional for congress to be able to create a regulatory agency fully outside of the executive's control, as who will check the congress's power? Appointment and confirmation exists so both branches must assent to all officers of then government
Yeah this is a silly argument. The check on the actions of independent agencies is the same as the check on the actions of all agencies. The executive obviously isn't a check on the actions of executive agencies...
It's not unconstitutional, it's already been done and the supreme court says it's fine.
They decide what is and is not constitutional, not you. And, contrary to what Internet armchair "textualists" will proclaim, most of the constitution is up for interpretation and actually quite vague.
We've been debating the constitution since the moment we lifted the pen. Or, er, quill. Have some humility.