Cars in the EU have aspherical mirrors that work like this: https://i.imgur.com/rJI3UR0l.jpg . Much like a stick-on but less unsightly. These are pretty good, but they're not installed in the US due to some archaic regulation or another. The Ford system with an inset towing-style mirror is great too.
I have a set of those on a Mazda Miata and the better version built right into the tow mirrors on my truck. I love them -- much easier to see into the large blindspots on both. I really wish that they were built into more vehicles. I trust that much more than blindspot warning lights.
https://www.amazon.co.uk/Blind-Spot-Mirrors/b?node=491998903...