KIS offers great real-time protection. Make sure you research online (official manuals, guides) for tips and information on how to configure it for maximum security.
If you want to test malware samples, I highly recommend doing so in a
virtual machine. Virtual machines are emulated computer systems running within an actual, physical computer, and have many uses, including malware testing. My personal favorite virtual machine deployment and management application is
VirtualBox which is free, open-source and reliable.
I recommend you create a system backup image of a known clean state of your system, which you can use to restore that exact state in the case of software malfunction or malware infection. (unless you don't mind re-installing your entire OS)
The software I recommend for this purpose is
Paragon Backup & Recovery Free Edition, however there are also other reliable alternatives, such as
AOMEI Backupper Pro or
Macrium Reflect Free.
Regarding what extensions to use in your browsers
There is definitely a great variety of add-ons which you can use, however one of the most important ones would be
uBlock Origin which blocks advertisements and malicious domains.
Other than that, you're good to go. Thanks for sharing your config with us!