Time for you to find a different dealer. You know, one that actually knows what the heck they're talking about.
There's nothing magical about the Clarity's OEM evse. I've used four different EVSEs on my '21 Touring, a mix of L1 and L2 (some do both), and the car exhibited the usual variation of miles on its Guess-o-Meter (GOM).
It appears that you may have an unreasonable expectation of what your GOM says after charging. It's a guess, and is based on your driving style during some amount of previous miles driven, as well as temperature. In winter, you can expect to lose 10-20% (or more!) of your range, depending on where you live. In really cold climes, losing 50% of range isn't unheard of. HVAC use becomes a large factor in energy use in really cold climes.
During cold weather, and if you drive with a lead foot, 35 miles isn't really all that bad. I'm in So. CA, and I routinely lose at least 10% range during winter in every EV I've driven. I also can get 50 miles of range in the summer, if I choose to be careful. I usually don't choose to.
Wait 'til summer, and drive like there's an egg between your foot and the go-pedal, and it's possible you'll see 47 miles on the GOM, or at least perhaps achieve 47 miles in actual EV mode driving. Think hypermiling. Note that the GOM is notoriously inaccurate.
If you're concerned about the state of your battery pack, there are tools you can buy that will allow you to see their health. Less than fifty bucks can buy you a Bluetooth reader for a smartphone, and an app to interpret the data. There are other threads on these fora to tell you how.