Thanks for taking the time to leave us your feedback. We're glad you enjoy our service! Apologies for the inconvenience. Our extension does not currently support storing settings, but that's a great suggestion. Given that you are only running Private Browsing windows, if you want your Settings to stick, you'll need to search from the site itself, not the URL bar. Accessing Startpage by bookmarking the Settings URL would be a way to cut down on having to change your settings every time.

https://support.startpage.com/hc/en-us/articles/4616244515476

Thanks for caring about privacy. Feel free to contact us at support@startpage.com to discuss other potential workarounds.