is it safer to use the icloud app?

I am having major security issues and am being hacked and cyberstalked by an ex. Months ago I changed my apple id and passwords several times. I wiped my two iphone 7 and ipad mini, restored to factory settings, and created 3 new apple ids (one for each device) I do use my HP all in one desktop as well. It was wiped and reinstalled windows 10. I am still having issues with settings being played with, not getting emails, phone calls, and text. I prefer to use my computer because it is easier to type and has a much larger screen. Is it safest to use the windows icloud app or to go to icloud.com in my Avast or Chrome browser? I am unable to access my icloud email at all on my ipad mini

and the two other devices are having issues as well. Help!!!