Another perspective is that the tempo is placed at the point of the tempo change, rather than what you want, which is to place it at a point in time after that change is supposed to have occurred.
Well, you are asking for a manual change (due to a non-standard placement of tempo), so please expect all solutions will necessarily be manual.
Since you want the tempo to appear over beat 2, you could try placing the tempo there, rather than at the downbeat.
Your desired solution is non-semantic, so it's coding will reflect that.