Welcome to the forums, solid first post.I think there are question marks around McGregor's physical state that complicate the situation at this point. It's fairly clear he has been enjoying his recreational activities over the past couple of years, and personally I think that we have already seen the results of this with the conditioning issues he has shown in recent fights.
However, assuming McGregor makes it to the cage in something close to peak physical condition I would fancy him to win this fight for a couple of main reasons:
1) In a general sense McGregor has proven himself to be an elite level fighter while Khabib has never really fought anyone at the very top level. RDA is his best win but I think RDA improved dramatically after that fight. Barboza was well ranked when they fought but I don't think you could consider him elite. Outside of that he hasn't really fought anyone. I think McGregor is a major step up in talent and has proved he can operate at a level that Khabib just hasn't fought at to date.
2) There seems to be an impression that Khabib's fights hit the ground immediately and stay there but this is just not the case. While obviously he has a very strong takedown game, it isn't absolutely untouchable and his takedowns stats reflect that. When you actually look back through his fights, he spends more time in striking exchanges than people seem to realise. I think McGregor's grappling is underrated, but more than that I feel like his distance management could keep this fight standing long enough for McGregor to capitalise on the MASSIVE striking disparity. I think the Alvarez fight is a clear blueprint here. Ultimately, I am 100% convinced that if a fight between McGregor and Khabib stayed standing for as long as all of Khabib's recent fights have it would end in a McGregor KO or TKO almost every time.
Khabib's route to victory is obvious, and there are major question marks around McGregor's lifestyle and its affect upon his physical condition, but if he showed up in shape I would pick McGregor to win. I also think Max would beat Khabib and I would love to see that fight made in the near future.