UPDATE
I finally received an invoice after going back and forth with them about incorrectly applying tariffs and predatory storage fees. I also filed a formal trade violation complaint with US Customs and Border Patrol for broker misconduct.
They dropped the storage fees and dropped the (illegal) stacked tariffs. Original amount they wanted was $869. New amount is $525. Of that, $382 is for import tariffs, which is correct and what I expected. The remaining $143 is additional DHL fees. And that's ridiculous, considering I had to pay $250 for shipping in the first place. But I expected to pay some fees for their broker handling clearance.
Merchandise Processing: $33
Duty Tax Processing: $17
Permits and Licenses: $28
Clearance Processing: $15
Under Bond / Guarantee: $50
They don't explain what any of this is for. But looking at their online calculator that spits out an estimated landing cost, most of this seems ok except the last $50 charge. But all in all, I'm finally in a place where I feel I'm not being screwed over.
It took 28 days, 15 phone calls, two trips to my local DHL hub, 33 emails, and a formal complaint to CBP.