No clue what’s best for a scooter. But last time I checked, both bicycle stores and workware garment stores had some nice options. Something like this, and with workwear there’s different looks and options available for every season:

https://www.strauss.com/de/de/warnschutzjacken/warnschutz-softshelljacke-e-s-motion-24-7-3210970-84511-1498.html

But there’s also basic safety jackets you can put on over your regular stuff for a few bucks. Just make sure the reflectors aren’t fake.