Me too. My 2011 Volt was the first GM I purchased. However unlike you, I have found the car to be very well built. The few issues I have had have been minor. I do expect a main battery issue at some point, hopefully a few more years down the road instead of now.
My positive Volt experience convinced me to get the Bolt EV. That has been very good s well. GM just replaced the battery for free, I got an extra 29 miles range in the bargain, and the battery comes with a new warranty. Very delighted. Might end up replacing the Volt with a Chevy EQuinox (based on the Ultium battery platform). Given that the Ultium batteries will be used in almost all GM EV's and given it's designed to enable swapping out bad modules with those that may have new chemistry, I expect replacement parts to be more readily available including after warranty battery modules.
I agree that the dealer experience can vary from one to the next. I'm fortunate to have at least two good ones available, though they rarely see me. I think the supply chain issues are the root cause for the BECM replacement delays. Not that that is much comfort if your car is sitting waiting months for a part. And being a low volume vehicle does not help. Now if you had a Silverado...