Google’s John Mueller said on Twitter that Google uses many different signals for canonicalization: redirects, internal ande external links, sitemaps, hreflang, canonicals, cleaner URLs, and other signals.
If the same page is available at different URLs, Google tries to find the standard version of the page. That standard version is the canonicalized URL.
Redirects are a signal for canonicalization, but they're not the only one. Internal, external links, sitemaps, hreflang, canonicals, cleaner URLs, etc — all play a role. Make everything align, give it time to settle, and leave cookies & almond-milk for Googlebot.— ? John ? (@JohnMu) July 31, 2020
Check redirects and more on your website
The website audit tool in SEOprofiler checks redirects and many other things on your website. Ensure that your web pages are error-free: