When You Unlock Mutators, One Of Them Is "Googly Eyes"
Select This*, Pick Covenant Rank 0 For An Easier Run, And When You Beat It The Achievement Is Yours!
- In My Opinion Umbra's The Easiest, Just Feed Your Train Guards To Get Through The First Two Levels.
*You Can Also Knock Out The "On Your Own" Achievement In The Same Run, It Is Another Mutator You Can Select Before The Run.
-Removes Your Champion From The Deck, Seems Hard But You Can Beat It On Covenant Zero With Some Work.
Good Luck!