Thousands of messages per minute in system console. Mac is slow by doing lots of things.

Long ago I was doing some sketchy stuff with my Mac and damaged the system. I can't recall what I was doing but almost sure it involved disabling some integrity checks or something. Now the Mac is slow by doing thousands of task every minute as per System Console. I'm almost sure the damage is reversible but I need someone who can have a look at it. I've downloaded EtreCheck and performing scans now. But they are not going too fast...

What can I do in the meantime? Should I post my console log?