The fact that this is no longer the case doesn’t necessarily need to change Guardians in any significant way, but if the movie was written to open with a Chris Hemsworth cameo and/or an explanation as to why he’s not in the rest of the movie, that scene technically is no longer necessary as that explanation will need to be part of Thor: Love and Thunder instead.
If that’s the case, we can just transplant the scene that would have been in Guardians 3 into Love and Thunder, and then we can keep it in Guardians too, because why not?