its a mix of two major things + whatever number of smaller issues:
- the game isn't done and is likely nowhere near optimal
- your card is dated, and newer stuff is going to demand that it work harder to keep up. Its a 2017ish era card, and nearing the end of its lifecycle.

it does not matter. In the default setup (not overclocked, fan working, case well ventilated) it can run at max capacity all day for years. If you think it is too hot, you can check those 3 key points, blow the dust out, validate the airflow, check the fans, etc.