The other thing we should point out about the timeline is that it is never going to be pinned down definitively until it has to be. When Favreau said between zero and two years, I really think he means it. As creative storytellers, they’re going to reserve the right to expand or contract that timeline however they need to so that they have the room to tell the stories they want. There is very little going on in the galaxy in this part of the timeline that acts as a major tentpole event, so the runway they have to play with can be as long or as short as they want it to be. It’s why the evidence presented above is all in vague generalities. There’s nothing set in stone and there won’t be until they need one. If a character like Rey were to be born and they dealt with that story on the show, it would lock them into a specific year in the timeline. Short of that, all of this is as much or as little time as the story needs for these events to take place.
Was Luke with Grogu for two years? Maybe. Does it matter if it was more or less? At this point, no.
Don’t expect a more definitive answer on this until long after the show has ended. If Favreau is saying it was two years at this point, that is not out of the realm of possibility, given what we know. And if you’re a creative, why would you want to lock yourself into a specific amount of time, one way or another? There’s no upside to defining it in stone. The story works just as well without a calendar on screen, flipping pages to show us the exact date.