You can easily upgrade to the mastermind TCU, not sure why your dealer is saying you can’t. I went the opposite and downgraded to the older TCU so I could do away with the handlebar remote, it took my Spesh dealer like 5 mins to do whatever changes in the software that needed to be done.
I think the issues you’re having with the weight is just the carbon vs aluminium frame. On paper the Shuttle AM Pro is a pound heavier than my Levo Pro, on the scales my Levo pro was almost 2lbs lighter.
Suspension wise I’ll agree, the stock set-up wasn’t very good as it bottomed out way too easily. I started with the cascade link, that made a huge difference. I’m now on the Cascade long link kit with a 230x65 shock and bumped the front up to 170mm. I own a ton of bikes and this is probably the funnest bike I own. Did you get the generic tuned RS SDU or the one that’s tuned for the Levo? There’s 2 different part numbers, the Levo specific tuned one is actually pretty good.