Does a clean result mean my whole site is healthy?
No, and the tool says so on every result. The inspection reads one public URL. It cannot see your server logs, your Search Console history, your redirect map, or the other pages built from the same template. A clean result on one page is a good sign, not a clean bill of health.
Reading The Results
Answer it for your own page
The inspection is free, needs no account, and takes a few seconds. It reports what is actually wrong with a page rather than what is generally true about pages.