First, there is no reason to ever install or run any 3rd party "cleaning", "optimizing", "speed-up", anti-virus, VPN or security apps on your Mac. This documents describe what you need to know and do in order to protect your Mac: Effective defenses against malware and other threats - Apple Community and Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support.
There are no known viruses, i.e. self propagating, for Macs. There are, however, adware and malware which require the user to install although unwittingly most of the time thru sneaky links, etc.
Anti Virus developers try to group all types as viruses into their ad campaigns of fear. They do a poor job of the detecting and isolating the adware and malware. Since there are no viruses these apps use up a lot of system resources searching for what is non-existent and adversely affect system and app performance.
There is one app, Malwarebytes, which was developed by a long time contributor to these forums and a highly respected member of the computer security community, that is designed solely to seek out adware and known malware and remove it. The free version is more than adequate for most users.
Uninstall F-Secure according to the developer's instructions. You can check to see if you've removed all of the supporting files by downloading and running the shareware app Find Any File to search for any files with the application's or the developer's name in the file name. For F-Secure software you'd do the following search(es):
1 - Name contains f-secure
Any files that are found can be dragged from the search results window to the Desktop or Trash bin in the Dock for deletion.
FAF can search areas that Spotlight can't like invisible folders, system folders and packages.
If you get warnings that the file can't be deleted because it is in use or used by another app boot into Safe Mode according to How to use safe mode on your Mac and delete from there.
Note: if you have a wireless keyboard with rechargeable batteries connect it with its charging cable before booting into Safe Mode. This makes it act as a wired keyboard as will assure a successful boot into Safe Mode.
It's important to remove all supporting files for F-Secure as it has installed over 25+ files, some running whenever the M1 is on, and that takes up considerable system resources.
Additionally, you're running low on free space as the report indicates:
Major Issues:
Anything that appears on this list needs immediate attention.
Low disk space - This computer is running critically low on free hard drive space.
Size: 494.38 GB
Free: 17.29 GB
Available: 29.84 GB
Base on this you wouldn't have enough room to download and run some system updaters as they require around 45 GB of free space. Also it's recommended to maintain a minimum of about 80 GB of free space for optimal system and application performance. You need free space for temporary system and application cache and swap files . Rebooting 2-3 times per week will remove those temporary cache and swap files and aid in the efficiency of the system.
