SAFe is for managers, Agile is for developers. As developer, you don't need to know SAFe and it rituals. SAFe is not heavy weight, it very lean for the problem it solves.

> It somehow promises to combine bottom-up agile with top-down date-based delivery commitments then hand-waves away the collision of these intractable approaches,

It OK to fail few early goals or dead-lines until right pace will be found.