Heeellllllppppppp!!!

You only need perfect beat grids if you intend to use sync 😉
Aligning beat grids in Rekordbox is actually easy but takes a tremendous amount of time, for disco tracks in particular.
Search “Rekordbox beat grid” on YouTube and watch as many as you can.

For my collection I make sure the grid is aligned at the downbeat. This helps sync effects to the track, like a 4 beat filter effect.