If you set the home page in Settings,On Startup . . . and then if the same page is what you want for the new tab, set that page (for your new tab) through this extension.
https://addons.opera.com/en/extensions/details/custom-new-tab-page/?display=en
Then every time you click on this extension icon, you return to your home page. I know this works. I haven't tried the extension lando242 provided.