You are constantly underestimating Roglič. He was second in Giro TT this year (a second behind Tarling despite a flat course) and third in Peyragudes. On a hilly TT course like in Rwanda, he is easily among top 5 favourites.Roglic doesn't have a chance. He is not that good anymore.
Of course, Pogačar is no. 1 favourite on a hilly TT course like that. And this might be one of the reasons he skips Vuelta (in addition to fatigue). There will never be a more suitable TT course and thus a better chance for Pogačar's WC TT title than this year. Add to that he wants to defend his RR rainbow jersey and finish the season with record 5th consecutive Lombardia.