I have called M2S a few times before and after the sale, they are great! Had a bit of shipping damage on my battery and it took just a phone call and 4 days to get the new battery and shipping label for the original.
I raced MTB competitively all around the east coast and Canada until 15 years ago. Now I am in my mid 60's, have severe heart issue as the result of chemo for my leukemia. I still remember some of my skills from racing that includes bike wrenching and shifting gears. No bike shop needed for adjusting shifting and brakes or really anything on the bike parts. The motor, battery, and controller are basically plug and play so no mechanical aptitude needed there. The LBS's that I visited have very limited, if any expertise on ebikes so not much help from them anyway. One shop actually slipped up and told me that they would call a dealer help network for ebike problems and had a minimum of 2 week TAT for parts even under warranty for very high end ebikes.
I am a tiny bit concerned about chain stress with all the power this thing has. It might be easy to break chain if you try to jump multiple gears but it does momentarily cut power when you shift so who knows. I broke a few chains racing so always carry a 'no tool link' and chain breaker in my tool kit jic. The power transmission with torque sensing is very smooth so not expected that to be an issue. Throttle use might be harder on the drivetrain but I am removing it because I won't use it. Actually it twists my tires on the rims at 4 lbs pressure on pavement with a fresh charge.
I just sold my dualsport adventure motorcycle but if I wanted a bike that was going to be used with a throttle, I would get a 250-300 cc motorbike rather than an ebike for sure. For me, an ebike is a toy that will get me in the woods or trails exercising and maybe to make the 12 mile ride to my boat once and a while.