Slow iMac 21" 2017, 8GB

Hello. My iMac becomes very slow after a few days of use. Memory slowly reach the limit of usability. Last year, with a fake Java update, I caught some kind of virus, and problems began. Following Etrecheck's report, and community advice on similar problems, removed some files, it seemed solved, but maybe it isn't. I know it can depend on the RAM memory (8GB), but since it cannot be opened normally, before doing so I would like to have the opinion of the Community.

I paste Etrecheck report.

Excuse me for my English, and thank you.