Why is my Macbook Air (2020) so hot?!

There might be a Run-Away Process or Application. Suggest opening the Activity Monitor >> View >> View ALL Processes. Look in CPU tab for unusual CPU usage and the Process corresponding to the usage and do the same in the Memory tab. This will help to identify the application or process. Understand - the Run Away process is probably the cause of the extra heat the computer is experiencing.

Second step would the Restart the Computer in Safe Mode . This will do a Repair Disk, clear cache files and only load Apple Software, extension and Fonts. It will load slowly - normal. Once logged in the computer will look and perform differently - also normal. Run this way for 10 - 15 minutes and test. If the computer appear to run not at hot - there might be an issue with your account.

Lastly must ask, Are there any AntiVirus, Disk Cleaner, Optimizers, Defrag, VPNs etc installed which should be removed as per Developers Instructions. They are useless, unneeded, cause havoc and interfere with the normal operation of the OS and may even Corrupt the OS requiring a Reinstallation.

It may help if once identified the process or processes you provided a list by name of them. Or, is easier - a Screen Shot of

Activity Monitor showing the offending process(s) by name and we can assist in more detail.

Your questions are important and will help to possibly return the computer to normal operation.