Does the OG meaning change depending on context or usage?

Yes, the OG meaning can indeed vary with different contexts and uses. At first, “Original Gangster” was a term for a respected, old-timer in the streets. Nowadays in texts and social media, the term OG is rather versatile. One can call another the genuine seasoned highly respected one, or even something original as in an “OG version” of a product or trend. Generally the connotation is positive. It was mostly by Ice-T that the word was introduced, and now it is a general, contemporary slang term.