M1 Mac Air performance degrades until restart

One of the only Adware / Malware trusted for macOS is from a Trusted Developer and Respected ASC Contributor the application Malwarebytes for Mac. It is free or paid for added features. Run the Application and it should remove the malware / adware. Once done, restart computer and test.

There are no known Viruses in the wild that self replicate and affect macOS. There are Malware and Adware that does affect macOS and are often times downloaded as part of an Application from Third Party UnTrusted Site and get installed along with the Application.

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. The Built-in Security of Big Sur is all that is required.

Any Third Party Applications that will interfere with the normal operation of the OS, alter, modify, remove or delete or attempt to do so is an invitation for disaster and may require a Reinstallation of the OS.

Suggest downloading the Application Etrecheck directly from a Trusted Developer and well Respected ASC Contributor. The application is free or paid from added features. Run the application with Full Disc Access ( Security & Privacy - Full Disc Access ). It will take a Snap Shot -  both the hardware and software. The Report will Not Reveal Any Personal Information. Post back the Full Report - copy and paste - using the Additional Text Icon ( 3rd Icon to last )

We can have a look at the report for possible issues and may have possible suggestions to resolve the issues.

This is one Very Heavily Configured MBA M1 with Several attached External Drives and many Modifications to the System. It, computer, might not perform as well as a more Robust MBP M1.Only suggestion is restart the computer more often to fee up Memory and Processes running all the time of for extended periods of time. That and Close unneeded Application when not in usage.

As per EtreCheck Report see below

Clean up - There are orphan files that could be removed.

Unsigned files - There are unsigned software files installed. Apple has said that unsigned software will not run by default in a future version of the operating system.

Kernel extensions present - This computer has kernel extensions that may not work in the future.