Thanks for your question. The temperature in your application goes up to 100 °C. This limits your options to models with a remote probe. Depending on the expected humidity level, you can find a suitable instrument from following product lines:
0-10 %RH: DMT340-series.
10-100 % RH HMT330-series or Indigo HMP-probes.

Varying pressure in your application has some effect to the humidity reading. To help you decide if it's needed to compensate this effect or not, please take a look at our humidity calculator: https://www.vaisala.com/en/lp/humidity-calculator .
This tool helps you to demonstrate the effect of different pressures.