Yes, it's safe.
Yes, it's safe.
If you're okay with your laptop getting warmer, just mount it on the wall with the lid up. This helps the fan move air more easily. Most of the heat is just being reused, but it’s definitely better than trapping hot air inside. Your concern about safety is valid—performance limits can happen if you block fresh airflow.
Are you achieving optimal performance while your desk remains shut?
Close the door, start a game or run a test. Record your result or frame count. Take the laptop out of the drawer and place it on top of the desk. Retry. Does the improvement exceed 5%? Yes if so, otherwise no.
Your laptop's specs affect speed. If it's top-tier, expect slower results. Otherwise, performance remains unaffected.