I think this is the fastest new tab/homepage extension I've tried, and the blank URL bar is just great, but a bit buggy with current Firefox sadly!

Worked fine to present google.co.uk as my home page (with the exception of the known problem that it does not grab the focus) until I updated to Firefox 77.0.1 2 days ago. Now FF puts up "Blocked by X-Frame-Options Policy" I hope that it can be fixed in an update.