I also had similar problems with iPhone and BT. Before it worked very good with an Android. What I've learned over time is that apple seems ti sabotage anything that is not apple. I had connection problems with my car, with my Sony BT headphones, with portable speaker. Alk that went away as I switched back to android.
I guess you're right. My bluetooth experience is Macbook, iPhone, Apple keyboard, Apple mouse and Apple headphones. Everything works extremely well. The thing that I like most is power indicator integrated with iOS and macOS. Allows me to charge those things before they run out of power. As long as you stay in the garden, things are smooth.
I have no idea, I've read reviews from some bluetooth mouse and reviewer mentioned that macOS does not display its battery level. I thought that it's proprietary.
My cars are all older, but my Android pairs up with a Kia Sportage almost immediately after starting the car. My wife's iPhone 11 sometimes takes several minutes. She ended up getting an adapter to connect audio to the 3.5mm jack.
