Apple AirTags are amazing, and I have them attached to pretty much all of my valuable belongings, even my bike.
【HIDDEN DESIGN】Hidden mode for added more security - keep your Airtag out of sight and protected from potential theft with our Typecase Airtag
Airtag Bike Mount, Hidden Bicycle Seatpost Mount Compatible with Apple Airtags & Garmin Varia, Anti-Theft Air tag GPS Tracker Bike Reflector Holder
5 places to hide an Apple AirTag on your bike
Hiding AirTag on a Bicycle (How to instructions)
How to hide an Apple AirTag on your bike (and why you should)
Using an Apple Air Tag to Track a Stolen Bike - Singletracks Mountain Bike News
How to hide an Apple AirTag on your bike (and why you should)
Apple AirTag: Bike tracking solution to rely on?
TagVault: Mountain Bike
Muc-Off's Clever New Product Allows You to Hide an Apple AirTag in Your Wheel - Pinkbike
Apple AirTags for bicycle tracking? BikeTaggr mounts attach to your bike for easy tagging - Bikerumor