Any on demand scanners installed? (If not then add two on demand scanners: MBAM and Hitman Pro or Zemana Anti Malware)
Is it Kaspersky AV or IS you're using? But any of those version it should capable to protect without any companion layer.
For Backup its better you have that like using the program from Built in of Windows or third party program like Macrium Reflect and placed those snapshot to your External HDD.
For Shared Account (optional): you may activate the guest account/limited user account so that all execution will be depend upon the administrator user.
KIS or KAV ?
Consider a back up solution
Add an on demand scanner(s) such as Malwarebytes Antimaware,Hitman Pro,Herd Protect,ESET online Scanner,Emsisoft Emergency Kit
CCleaner or Privazer
Chrome extensions ? such as uBlock,WOT,HTTPS Everywhere