You can create a GSC account for your preferred version once you have tested to be sure that requests with www land on the same URL without www and your logs show a 301 server response for that request. Don't forget, if you had a sitemap for the www version that you delete that sitemap.

Thanks for answering not2easy, let me see if I understood correctly:

-Is there no problem sending to G from the new account what was already well indexed? (because some were indexed correctly without www). Or should I only send you the links that you indexed incorrectly?

-As for the sitemap, the only one I had sent him was an xml with all the urls without www... that's why it also caught my attention that he had indexed some with w. Do I 301 and resend the same sitemap?

You don't need to “send” any specific, individual links. Just make sure GSC has both the with- and without-www versions of your site, AND make sure you have a canonicalization redirect (with/without www, AND http-to-https). Ask in the relevant subform--IIS or Apache--if you are not sure you've got it right.

G will find your sitemap if it is either in a standard location (example.com/sitemap.xml) OR your robots.txt says where to find it. In any case the sitemap is an optional extra; if the site is properly designed, they will be able to find all pages anyway.

lucy24 is right, you do not need to have a sitemap, my suggestion is that if you have submitted a sitemap previously with www that you create a non-www sitemap and use that with your non-www GSC account. Google sees the www version and the non-www version as two different sites.

Because you have said that Google has indexed both versions is why I suggested that you test to be sure that requests with www land on the same URL without www and your logs show a 301 server response for those requests.

Thank you very much for responding, I will do so.

I take this opportunity to ask within the same topic: Why were the URLs indexed by G that had www are all indexed with the favicon and those that did not have www (which are the ones that interest me) were all indexed without the favicon?
...and how could I solve it?

You don't want two versions to be accessible on your site. That would be like two duplicate sites. Google sees them as two separate sites with the same content. If you want to index your non-www version, all traffic needs to be 301 redirected to the non-www version.

You need to have a non-www version listed in GSC and if you have a www version in GSC it should go away as soon as you verify the 301 redirects.

If Google can index the www version of your favicon, then it is not correctly redirecting all requests. How are you redirecting?