For things like LEGO they are mostly specific sets, so they get built and displayed like models by my kids. Rarely to they build random stuff like I did when I was little, with only a small amount of LEGO.
When my kids come home with gift bags I feel like screaming.
The plastic junk is just collateral damage.
as a parent i would make that explicit, in order to be inclusive, i would ask/demand that no presents be brought to the party. any friends or family who do want to give a present should do that in private before or after the party, and all present are also to be opened after the party when the guests are gone.
that avoids a number of problems. the birthday kid can focus on the party and the guests instead of being focused on the presents. any disappointment about the "wrong" presents is hidden from the giver. givers won't be embarrassed or judged in front of the party if their present is somehow inferior to others. or givers can't brag about their cool present, and also the kids can't show off what cool stuff they got. really wrong presents can be ignored, returned, passed on without any fuss....