Yes he has, but if Mitch want Loffler he will get her. Doug is too important to waste. He can stay in the house where his value is known and as Chair of the Judiciary he would be invaluable. There is plenty of time, we cant play with losing a senate seat.
As someone else here on FR pointed out a few weeks ago ... By running to become the junior Senator from Georgia, Collins is basically giving up his job as captain of a Navy destroyer to become a deck hand on a merchant ship. Something about this whole thing strikes me as highly irregular.