FYI, there’s currently a glitch going around where, if you pop 300 balloons and accept the achievement in Nook Miles, it’ll cause balloons to stop spawning on the island. And since they’re required to be popped as part of Bunny Day, well…unless Nintendo sends out a patch soon, you’re all basically screwed. Currently one workaround is to create a second user on the Switch, and I’m pretty sure the glitch only kicks in IF you accept the Nook Miles for that achievement, although some users say they did what I suggested and the balloons still didn’t spawn.