Not a trend IMO. I wore multiple bracelets in elementary school. All that’s changed is the price tag
I think it depends on perspective. If you see a bunch of luxury stacks on social media (define that however you want) it might seem like a trend. Especially with this new (but kind of not) “quiet luxury” trend going on.
Be aware of your surroundings and wear your bracelet(s) in good health!
I've always loved the look of stacking bracelets. I think it's fun and creative. I only have two Cartier Love bracelets stacked—and probably don't plan on getting anymore—but I still love the look of it on other people.