Will the shark fin on the 2023 Lavida loosen and cause water leakage?

It's a screw.

No way, but mine has been fine for so many years.

It seems like the 2023 model uses screws instead of adhesive, right? Mine's getting loose too, and I'm not sure what to do.

It shouldn't happen. The shark fin is fixed on the car roof with double-sided tape, and the roof itself has no gaps, so it won't cause any leakage.

It shouldn't be the case. That shark fin is just glued on, not fixed with screws. You can check it out.