Duping gravity blocks with the End

So, long story short you can dupe falling blocks. (e.g sand, concrete powder, anvils ect) I haven't tried it, but you might be able to dupe Minecart Chests. (like putting shulker boxes and in the boxes have netherite, ect). this youtuber made a tutorial on it; https://www.youtube.com/watch?v=xPUoX8XgQmQ&t=156s

idk if this was reported or not but here ya go!