My guy, it means literally nothing. Not a thing. Time of possession was an important stat that coaches thought mattered in the '80s. Not a single advanced metric or any analytic has any correlation at all to TOP. It's literally meaningless.
Case in point: Who has the best offense in the country? Oklahoma...bar none. They are just slaughtering people on offense and have been for several years now.
They are 45th in the country in TOP. They were 90th last year. It literally means nothing.
To answer your other question, as to why Miami is high in that stat while still having a bad offense, it's the same reason this thread was started. Because the offense is incredibly slow. Also, the defense has been giving up more big plays than in years past. So Miami has a 7 minute drive because we're working at a snail's pace to stall inside the 20 and miss a FG, and then you give up a quick big play. We've given up 3 plays so far of 60+ yards on defense. Nobody in the country has given up more. Last year we gave up 1 in the entire season.
So the offense is plodding, then the defense gives up a huge play, and the offense is right back on the field. TOP....check. Winning games....nope.