Can't add Safari bookmark

I deleted the Safari.plist file as suggested in the link, and then imported my bookmarks from their backup. That seemed to solve the problem. Interestingly the com.apple.Safari.plist file does not exist in the Preferences folder. Must be something new with Mojave to eliminate that plist file.

I need a bit more help. I like Safari to launch with four particular tabs. I get to them with "New windows open with:" and point to a bookmark folder with the four URLs. A new (blank) page opens when I click the +. However it suggests Frequently visited. I would like no suggestions when I click the +. How can I set that up?

Tried the obvious, rebooting and relaunching Safari. Thanks for the link. I'll delete the plist file. I do have a bookmarks backup. I do that every 2 weeks.

And Malwarebytes shows nothing. Etrecheck shows nothing. I''ll go with a corrupted plist file.