Virus-like problems

Hi. I am using iOS 10.2. I am writing on my iPhone 7. I've been having a series of glitches: Settings that seem to auto-adjust despite restrictions, duplicate log-in screens and duplicate authentication code messages, passwords that are recognized only on occasion (not mistyped, not in keychain), blocked access to Apple Care service (but I hope not this forum), lost docs, options that are gray-out only sometimes, unrecognized activity like an unknown telephone number showing up in reminders (junk number, now blocked), aliases that I can't remove. I decided to reset my Mac Pro laptop to factory settings (it wasn't working well). I didn't restore it from backup; the data is on a g-drive. I had also cleared and taken all my Apple devices off iCloud then as well. All of this was done a week ago. The problems didn't go away. I am horribly unsavvy with tech. But I wondered if it was perhaps related to a browser or server. I was checking my Safari history, and I saw gstatic.com. I wasn't sure what it was, so I typed gstatic into Search. I saw articles about a virus. I cleared my history. But gstatic.com (as 0 bytes) shows up in Settings > Safari > Advanced > Website Data. Is that a concern? Could it have triggered some of the problems I have been having? If so, what steps should I take? And is there a particular device I should start with? My devices are all Apple products. I haven't yet researched this. I thought I would start here. I am not at all tech savvy, but I do take the standard security precautions of regularly changing passwords, always changing passwords in response to any message about suspicious activity, trying not to click on unfamiliar links, using 2-factor authentication, etc. I don't have unusual apps or software; my web browsing is very limited. I appreciate any help you can offer. And sorry for the over-sharing and exceptionally long question. Thank you!