MacBook heating issue

Try an SMC reset and a PRAM reset (hold the PRAM reset for at least three chimes or a full minute).

Run the Apple Diagnostics.

If the issue still occurs, then run EtreCheck and post the report here using the "Additional Text" icon which looks like a piece of paper.

I don't see anything that stands out although I am not familiar with "MobileBrServ" app.

Maybe it is just the computer getting older where the heatsink thermal compound is drying out causing the laptop to run a bit hotter than normal. Or maybe one of the browser plugins is causing a problem. Web browsing can heat up a computer since some web pages do run a lot of code on your computer.

Maybe someone else will be able to add something more.

Edit: Maybe you should try creating a new admin user to see if you experience the same issues. If a new user works, then a login item or plugin is likely the cause of the heating issue.

https://support.apple.com/guide/mac-help/set-up-other-users-on-your-mac-mtusr001/mac

Yes, but locating the cause can sometimes be tricky.

Creating a new user account and using Safe Mode are two ways to try and narrow down the location of the issue. If you mainly use Safari, then the Internet Plug-ins are the most likely cause or it could be due to the websites you are visiting.

You can try using Activity Monitor located in the Utilities folder to see if you can identify the process utilizing the CPU the most.

You can also run Disk Utility First Aid on the drive to see if the file system needs any repairs.

Pay attention to how you a resting the AIR. Not on lap, not on pillows, not on bed, not on anything to prevent air flow underneath.