1. Your baseline
Values are entered by you and saved to local browser storage. They are not fetched from Google.
2. Inspect page HTML
Choose a downloaded HTML file or paste the HTML source. This checks the supplied document, not your live website.
Dynamic rendering, link health, robots rules, server responses and Core Web Vitals require a real remote crawler.
3. Your next best move
4. Track a growth experiment
This is an experiment journal; before/after changes alone do not establish causation.