Covington.
The last fight of RDA when he was fighting a wrestler was against Jason High. And High is nowhere near Covington level, yet he was able to take him down few times and control on the ground.
RDA's kryptonite were always wrestlers (Khabib, Tibau, also Guida to some level). And we cannot say if he improved or not in this aspect because his last 9 fights have been against guys who don't implement the dominant wrestling strategy. Also, Colby is way bigger and stronger, c'mon RDA looked small against Tarec.
Of course Rafael has the striking advantage but you cannot strike if you are being taken down all the time. Covington will 50-45 him and all of you sherdoggers will think ,,how the fook did this happen" and start calling RDA a past-prime bum, because all that you see is Colby's striking against Maia.
And I'm not saying this as a fan, I don't give a damn about Cringe Colby.