A tutorial on how to add Bluetooth functionality to a Skoda STREAM radio - this one is from a 2008 Octavia, pre-facelift.
This method relies heavily on the AUX-IN being activated on the radio -- if your car doesn't have that option (double-press on the CD key), probably the best advice is to buy a STREAM MP3 that has it activated - these are now ~20€ in good nick.
Parts:
flat silicone type-c type-c cable
https://bit.ly/4klw9PJ
type-c usb pd supply
https://bit.ly/44XAweR