Insurance totaling my car at ~49% using high salvage value and low ACV. Is there a way of not totaling the vehicle and getting a repair?

Hi everyone,
Looking for some advice or real-world experience with a total loss situation.I’m in Illinois and have a 2020 Mercedes GLS 450 with low mileage (39,000 miles) that was recently declared a total loss by Progressive after hail damage. Car has clean Carfax, maintained at a Mercedes dealership and in impeccable condition. Our goal is to repair the vehicle and keep it, not total it, which is why we’re trying to understand if there’s any realistic path forward.
Here are the key numbers:
Insurance ACV: ~$37,300
Independent appraisal: ~$42,100
Repair estimate: ~$18,600 (insurance-approved)
Salvage value (IAA): ~$23,500

What doesn’t make sense to me:
The car is being totaled at ~49% repair-to-value ratio; They claim they can total it at their discretion even below typical thresholds; The salvage value seems extremely high, which is pushing it over the limit; If the ACV were closer to actual market (~$42k), it would NOT be a total loss..
From my perspective the high salvage value suggests strong market demand, but low ACV contradicts that.
So my questions: Is it normal for insurers to total a vehicle at ~50% based on salvage value alone? Can salvage value quote from IAA be challenged or verified? Has anyone successfully kept a vehicle from being totaled in a situation like this?
Is it worth invoking the appraisal clause at this stage, or is that unlikely to change the total loss decision?
Not looking to drag this out unnecessarily, just trying to understand if there’s any realistic path to keeping the vehicle or if the outcome is basically locked at this point.
Appreciate any insight, especially from adjusters or body shop professionals.