It’s normal. My '23 Rav4 is the same way. The opposing vehicle is just over too far over, for the sensor to see. It also does it going around a turn. It’s my biggest gripe with the Auto Highs. They worked so much better in my '17 Rav4, because you could still manually turn them off, while in Auto Mode, without turning Auto Mode off.

Not with 40k original miles. You’re not paying $500 for any working car, and in good condition anymore. Those days are long gone.

There’s no DIY for this. You need a new door. You can use touch up paint, but it’s going to look even worse. That’s also not going to take the dent out. If you’re really trying to avoid using insurance, your best bet is to call around to local junkyards, and try to find a door that’s in better shape. If it’s the same color, even better. If not, you can then get a body shop to paint the door for you.