Update 2025/01/30
EA has implemented a non-fix for this. This means that the items are no invisible (most of them) but still there. The overlapping festivals seem fixed but the objects are not....
Ideas
crinrictAnother "fun fact"
Using the same old save file with lot of garbage, called File A
File A loaded into game after patch -> saved directly as new save File B
File A loaded into S4S -> saved directly without deleting anything -> File C
File A 64MB, File B and File C 44MB