How can I reinstall existing MacOS on my MacBook Pro 2019 13"?

"Yes! Look for the OS installer on your system you may already have a copy. If you do you can then create a bootable USB-C/Thunderbolt3 external drive. Otherwise go to the Apps Store to download a copy.

Heres’ how to setup the USB drive macOS Monterey: How to create a bootable installer drive

Note: They have a small phrasing error calling out Big Sur you don’t need to worry they are assuming you are upgrading.

Once you have this setup you can the reboot using the USB drive to run the OS installer.

I do recommend you first backup your stuff first! And just re-installing the OS most likely not fix your issue as the Older OS structure and some settings are still present. If you are sure you have a OS issue then most of the time I end up wiping the drive down and then set it up afresh. Re-install your apps directly from the Apps Store or app publisher, If that’s not possible install a good antivirus app to first scan your backup drive to make sure you don’t re-infect your system."