Actually my Alexa will respond on my phone. Lock screen or not, she responds to me. Actually as anyone knows, at times you don't need her as well. Lol. But yes, the Alexa Auto is just a different version of any other Alexa. Just made for autos and packaged with a car charger. Different way to charge and smaller device, that's all.
Now I will say this much. My head unit on my bike has me seriously spoiled. It's one of the few units I've ever seen to adopt Alexa. For instance, I can have my GPS going, music playing and receive or dial out plus ask Alexa where to pick up the best hamburger at. Pretty much feels like my Note20 Ultra is built in as well. Only thing I have to worry about is controlling the bike and watching for others. I just talk to the stereo if I need help and it's done, hands-free.
Here's the link of what I have if you want to go that route.
On edit: I have Siri as well.
https://forums.androidcentral.com/e?...token=kHYljRqn