That said, I don’t necessarily buy that Thunderbolt Ross has been a Skrull since The Incredible Hulk.
As a general, Ross Skrull could only go so far dealing with Earth’s superhumans, but in the political realm, he had more freedom to carry out his agenda, i.e. the Skrull Empire’s wishes.
As for giving himself a power boost, if Ross Skrull were to be physically transformed, that’s be an intriguing way for the MCU to adapt Red Hulk, though I doubt he would be crimson-colored.
As one of the commenters on the Reddit thread pointed out, Ross was “far more aggressive and less diplomatic” in The Incredible Hulk than he was in Captain America: Civil War, so perhaps the replacement occurred sometime between those two movies.