2018 Spyder RT Won't Shift - where to start de-bugging?

[SpyderGin]

Hello. I hope there is some wisdom because my Spyder is about to head to the junk heap.

2018 Spyder RT Limited was bought new in 2019 from the dealer. Just over 4000 miles on it now. The first time it entered the shop, it was about six months old because the parking brake was stuck "on" and wouldn't turn off. It was in the shop for five months before I got it back. I blame the shop for that, they blamed not being able to get a part, but I got it back and went back to riding. Seemed to be fine. I had to let it sit for a while, about a year, because I had neck issues and finally had the surgery to fix it so I could ride again. I keep it in the garage, covered to keep the dust off, and on a trickle charger. The battery did go bad after sitting for so long, so I got a new one and took a short ride with no problems. I had the recall for the sprocket, so I took it into the shop to get it checked, and while there, I said to give it an oil change and a full-service front to back to ensure it was good. $2000 later, I rode it home (about 10 miles) with no issue. Rode it to a doctor's appt about 5 miles away, no issue. I went to get on for a weekend ride, tried to get it into Reverse, and it wouldn't go. After the third try, the dreaded exclamation point came on, and it had two error codes (it's still at the shop now - I don't remember the exact codes). I had it towed to the shop because nothing worked to get it into gear. Starts fine, everything works fine, just won't go into gear. The shop just called (two months later) to say that BRP recommended a software update, and that was done. That still didn't fix it. So, the next recommendation from BRP is to open the clutch and look for a potential problem. The shop says the estimate is $6000 or more. And that leads us to the junk heap.

I've had enough of the shops. They keep it for months every time there is an issue, and when fixed, it costs me an arm and a leg, and clearly, it's always going to have problems. I just downloaded the mechanics manual, and we'll get it towed back home because I'm not paying that much money for them to look for more problems. Surely this problem has happened to someone else? I'd like to know where to start debugging this problem other than tearing the clutch apart as the first step.

All recommendations are very much appreciated.