This paper is shit.
https://jhap.du.ac.ir/article_488_8e072972f66d1fb748b47244c4813c86.pdf
They proved absolutely nothing.
For instance, they treat physics as a formal axiomatic system, which is fine for a human model of the physical world, but not for the physical world itself.
You can't say something is "unprovable" and make a logical leap to saying it is "physically undecidable." Gödel-incompleteness produces unprovable sentences inside a formal system, it doesn’t imply that physical observables correspond to those sentences.
I could go on but the paper is 12 short pages of non-sequiturs and logical leaps, with references to invoke formality, it's a joke that an article like this is being passed around and taken as reality.