Mageia forum

Is there any kind of diagnostic tool in Mageia 6 to examine whether the distro is working properly or nominally, or if there
is any possible malware ?

My only way of testing it is to reboot and watch for anything unusual and test a few games and other programs to
see if they are behaving weird.

I have limited knowledge of HTOP, and would not know if the processor or memory is being over used in an
unusual manner.

I heard a vague rumor that ClamAV really doesn't do much.

This is pretty vague. First you ask about malware detection, then about diagnostic tools for ressource consumption like htop - what are you actually looking for?

For the first question, there are various tools like rkhunter, chkrootkit and even the regular msec scans which Mageia runs automatically.
There are various forum threads about this topic, please use the search function for that.