Hi Liv,
There aren't quick solutions for these cases.
My usual approach is to rely on Google, its algorithm will eventually get the canonical tag.
Its pertinent to understand that a canonical tag DOES NOT prevent a page to be indexed. The idea behind this signal is that Google would show the canonical version of the URL when it could have been the actual page.
I need to clarify this case, because when performing a site: search we will often find that canonicalised page there, but it usually does not get any traffic from Google.
Another thing to consider IS UP TO GOOGLE to decide whether to honour and consider your canonical suggestion. I'd try that page in the URL inspection tool to see what Google is considering to be the canonical version.
And, last but not least, canonical works when two pages are (almost) identical, this is not a simple way to clean pages from google's index or to softly redirect traffic from one page to another without server redirects, I've seen this and many clients were really furious because it didn't work.
Hope it helps.
Best luck.
PS, just in case other users need it, some resources about canonicalization: