Human-Speed Website Autofill Script

I have to move batches of 501 records (8 fields each) from a spreadsheet into a secure website. Three of those fields come from drop-down menus, the rest are plain text. After each row the site’s “Next”... (Budget: $100 - $500 USD, Jobs: Automation, Google Sheets, JavaScript, PHP, Python, Selenium, Software Architecture, Web Scraping)