Most of that cost is modem I'm sure. The ESP32, RP2040, and all the support hardware around both add under $5 to the BOM.
There are a bunch of boards with a combo of RP2040 and ESP32, probably because the RP2040 has the PIO accelerators and the ESP32 is much more rigid with I/O. If anything, I'd ditch the ESP32 on this board if your application doesn't need WiFi or Bluetooth.
Edit: I didn't realize the ESP32 is the -C3. It's no slouch, but your code shares the single risc-v core with the radio stack. So it's better off here as a dedicated radio processor and letting the RP2040 run your application if you need more grunt than polling a sensor every so often.
Try running your dryer with the lid propped open a bit. Most Sunlu dryers don't have a way to get rid of the humid air pulled out of the filament.