Who is in control of my Mac?

Question

macOS

Recently, my Mac has become noticeably slower.
When I write text, from time to time the cursor started jumping past the text and sometimes switching between tabs.
Today I wrote a post in VK, it was being edited. I haven't published it yet!
While I was browsing other tabs and then switching back to the page - I saw someone change my text to "joking statement".
Here is a screenshot of my processes

Answer 1

The answer was moved to the comments, probably due to clarifications.
Theory: a malicious script or extension in Google Chrome, if the author does not confirm, the answer will be deleted.