Bhagavad Gita, Chapter 6, Verse 41

Having attained to the worlds of the righteous, and dwelling there for everlasting years, one fallen from Yoga reincarnates in the home of the pure and the prosperous.

Effort that didn't fully finish still lands somewhere genuinely good, not nowhere.

Krishna spells out the real outcome here, not punishment, but real continuity. Sincere but unfinished progress is described as carrying forward into real, favorable circumstances, not simply disappearing.