1. The MacBook Pro is obsolete, I know but still works well. A new 16â   MBP is planned with the M1max chip Jan 2023
2. Battery to be serviced, was done but it still reports to be serviced.
I do suspect the repair shop to have fitted a Chinese battery. (Vietnam)
3. what to do: Configuration Files, delete?:   /etc/hosts - Count: 212 ?
4.  Antivirus software: Apple and AVG, has been uninstalled
5. What to do with these, delete?: 
Plugin: /Library/Internet Plug-Ins/nplastpass.plugin
    Plugin: /Library/Internet Plug-Ins/AdobeExManDetect.plugin
    Plugin: /Library/Internet Plug-Ins/Flip4Mac WMV Plugin.plugin
    Plugin: /Library/Internet Plug-Ins/SlingPlayer.plugin
    Plugin: /Library/Internet Plug-Ins/SharePointBrowserPlugin.plugin
    Plugin: /Library/Internet Plug-Ins/npDDRia.plugin
    Plugin: /Library/Internet Plug-Ins/EPPEX Plugin.plugin
    Plugin: /Library/Internet Plug-Ins/DirectorShockwave.plugin
    Plugin: /Library/Audio/Plug-Ins/HAL/InstantOn.drivec
6, what to do, delete? Preference Pane: /Library/PreferencePanes/Flip4Mac WMV.prefPane
7. Can I delete: 
Startup Items:
    tun Path: /Library/StartupItems/tun
    tap Path: /Library/StartupItems/tap
8. Can I delete?   
[Not Loaded] com.piriform.ccleaner.engine.xpc.plist (? 0 - installed )
[Not Loaded] com.piriform.ccleaner.services.submit.plist (? 0 - installed )
    [Not Loaded] com.piriform.ccleaner.services.xpc.plist (? 0 - installed )
    [Not Loaded] com.piriform.ccleaner.uninstall.plist (? 0 - installed )
    [Not Loaded] com.piriform.ccleaner.update.xpc.plist (? 0 - installed )