Chrome menu is next to the the Apple at the upper left (when Chrome is running), but the ••• and Settings gets you to the same place.
If something other than Google is in Manage Search Engines but cannot be deleted, you have indeed been 'hijacked' – I'd delete and reinstall Chrome.
At the bottom of your computer screen, in your Dock, right-click Chrome.
Select Quit.
Open Finder.
Go to the folder containing the Google Chrome application on your computer.
Tip: It may be in your Applications folder. If not, go to File and then Find, and search for "Google Chrome."
Drag Google Chrome to the Trash.
Delete your profile information, like bookmarks and history:
At the top of the screen, click Go and then Go to Folder.
Enter ~/Library/Application Support/Google/Chrome.
Click Go.
Select all the folders, and drag them to the Trash.