I think the problem with Solo is inconsistency in production and components. Some people here report that they have had flawless operation since day one. Others - different story altogether. I'm in the same boat as you. My first Solo was problematic in many ways, including a defective controller that needed to be returned for replacement. The problems, combined with the ridiculous gimbal launch delays caused me to return it for a refund. After the gimbal became available I decided to give 3DR a second chance and re-ordered. Solo #2 had massive shake problems which I couldn't resolve with prop balancing and multiple calls to tech support. So Solo #2 went back by RMA. It was returned after 5 weeks refurbished and with more stable flight but a badly malfunctioning gimbal. So the gimbal went back on RMA and was replaced. Now with the new gimbal flight and gimbal are stable but I am having frequent problems with losing wifi multiple times during every flight with the controller powering itself off and Solo executing RTH. Also one or more motors are developing a very different sound which makes me suspect I am in line to be one of the next motor failure victims.
So, long story short, you are not alone. Am I also disappointed? Of course. Am I pissed? Not really. I partially blame myself for being sucked in by the slick marketing. And I have learned a few valuable lessons. I will never again be an early adopter of any new technology which is just an idea at the time pre-orders are being taken. And when one manufacturer dominates the market for a tech product it's probably best to stick with them.
I do agree with all those saying that 3DR customer support is excellent. They always have stepped up for me and repaired or replaced whatever was not working. The problem is that only goes so far when the product itself is continually plagued with ongoing issues and the replacements of replacements also have problems.
Some members of this group take it personally for some reason when you post about your problems. I have experienced that the same as you. I don't really get it. I'm really happy for those who haven't had a single problem. I'm not sure why they get offended that you and I and others have had lots of problems and are looking for answers. But there are also lots of great participants here who will offer help and suggestions.
So the bottom line is, I haven't given up on Solo yet. I have too much invested into it in time and $$$ to let go now. But I am becoming less optimistic.
I haven't flown yet on the 2.0 FW. I'm hoping it will fix all of my issues and it will be rainbows and unicorns from here on out