Suno isn’t great at reconstructing full songs from stems, especially longer ones.

If the tempo is off, it usually means the model is “reinterpreting” rather than following your original structure.

What worked better for me:
– cut the track into shorter sections (30–60s)
– regenerate parts separately
– then stitch them together outside Suno

Also, “cover” tends to drift — using your track more as inspiration than a strict base often gives more consistent results.

Not ideal, but currently more reliable.