Will upgrading to 32GB of RAM increase temperatures in a small form factor PC?

No, 32GB RAM won’t meaningfully affect temperatures in an SFF PC. RAM generates very little heat compared to your CPU or GPU — going from 16GB to 32GB adds maybe a watt or two. The real issue is airflow obstruction from extra modules, not the heat from the RAM itself. Focus on your CPU cooler, fan configuration, and GPU clearance instead.