Oh it's not complicated, my way is just overcomplicated "for fun". You just make a post like an image, but use a link to a .gif or .webp file (though webps don't work entirely right on Sync). You have to have it hosted on an external site though (any file/image sharing site like imgflip/imgur/catbox.moe) since uploading directly to a lemmy server makes it not animate. Sorry if that doesn't make sense haha, I'm not sure if I explained it well