Charred grain under the crumpled wall of Jerico are just on top of the Santorini ash layer.
means that Thera/Santorini happened before Jericho but after/contemporary with Exodus? Your post indicates that would put Exodus at an earlier date than generally assumed (not sure what that generally assumed date is)? Is 1628 BC before the generally accepted dates for Exodus? I'm just not that conversant with the accepted dates.
Yes, see below
"The early date is usually placed in the middle 15th century around 1440 BC, while the late date is usually assigned to the close of the 13th century around 1290 BC. The early date relies most heavily on two specific biblical passages understood literally, while the late date relies on a more general view of the nature of Scripture combined with archaeological evidence. "