Slightly off topic......your experience of the SL power delivery is exactly the same as what I find. Are you running the latest software update for the motor? I'm still on the software that the bike came with in October last year and I wonder if the latest update fixes that surge you get in level 3
I recall one of the updates addressed this issue specifically. My LBS is a former employer (bike mechanic) and I would hang out in the shop while they did the firmware updates. The updates make a significant difference in the power delivery and how the bike rides.
One negative experience: the motor stopped delivering assist at 2500 miles. Mission control showed everything green, but motor would not respond. Specialized quickly sent a new motor and and I was back on the bike in 3 weeks. I rode the bike right after I installed the new motor (with out firmware updates) and it was genuinely terrible. Had the firmware updated and it was back to being great.
OP, I had the Levo comp originally. It was a fun bike, but it was 52 pounds (alloy) and being relatively fit (I ride a Stumpy 50% of the time), I would maybe use half of the 700wh battery on big rides - 30+ miles. The FF motor was so powerful, I would ride in dialed down eco and trail modes. My LBS shop manager suggested the SL and generously let me return the Levo and I picked up the SL Expert '20.
It's a very different bike, and I absolutely love it. True, the '20 Expert was under spec'd for the price, I've literally replaced every stock component. I've made it a long travel hover bike to complement my light weight '21 Stumpy - Pike Ultimate 160mm and a DPX2 w/cascade link. It comes in a just a hair under 39 pounds w/ XT four piston brakes, the upgraded suspension and Grid tires w/ pedals. Best of both worlds, rides like a long travel trail bike, but climbs like an XC bike with pro rider legs. The power is less than the FF Levo, but I would not characterize it as "weak".
I don't ride with other E-bikes, so YMMV. If I did ride w/ other E-bikers, would likely be on a Gen 3 Levo.
As far as range goes, being fit I can get 3-4000 ft of climbing and 30-35 miles on the internal battery with usually about 15-20% battery left. Using the range extender, I can get 5000 ft and 35-40 miles with about 15-25% battery left even when using higher power levels in eco or trail. One thing I have noticed since the last firmware update is the motor seems to have more power output and the battery drains a smidge quicker. Not sure if that's in my head or real.