Isn’t it actually against the law/constitution to wear the flag as clothes?
No. It’s against flag code, but there is no real law or enforcement of the flag code. If you do break it, I will immediately assume you are not a patriot and instead you are a nationalist because you didn’t take the ~5 minutes to look up the flag code.
I will only assume you have no taste, because it’s just a flag and I don’t care. But that looks horrible.

I don’t think patriotism and flag code are necessarily linked.

Example

Military veteran detained after burning American flag in protest at Trump’s executive order

The Independent
Flag burning isn’t against the flag code. Flexing your 1st amendment is definitely patriotic.
Huh, TIL. I guess throwing it on the ground was against flag code but not the actual burning.
The burning after it touches the ground is actually what you’re supposed to do according to the flag code.
That, I also learned, is a common misconception. Flag code just says pick it up off the ground.
No? Maybe like military flag code
Not since.lime 1970s

The flag itself, but not clothes designed to look like the flag.

IOW: if you’re caught in a sitcom type situation where you lock yourself outside of your house and the only thing you have available to cover your fetus production apparatus is the stars and stripes you fly on your front porch because you’re a jingoistic weirdo, you’re going to be breaking the law one way or the other.

Conversely, the above fashion crime is as legal as brandishing military equipment while shopping in some of the more backwards parts of the country.

Flag code is advisory and != law. If you’re naked and wrap them bits in the flag, no laws are broken.
It’s against flag code, which is not law. It’s just a set of guidelines.
I think its against the flag code to wear an actual flag as clothes. Not to wear clothes that look like a flag.