In all honesty the events of Timeless should have frozen his advancement forever.
Kim destroyed the universe for selfish and substandard reasons.
Someone that criminally irresponsible should never be given their own star ship, and should never be allowed to run free that they could come into possession of their own Starship outside of Starfleet with which they could destroy the universe at whim again whenever without oversight.
In Endgame, any other Captain would have opened fire and destroyed Admiral Janeway if she had led them to believe that she was about to destroy the universe, because the needs of the infinite outweigh the needs of a 140 idjits.
The crew of the USS Rhode Island should have mutinied because their captain was clearly insane and suicidal.
Destroying reality is in his nature, and it's unforgivable.