About an indexing situation

Hello there.
I am facing some problems:
Both Google and Bing refuse to index the entire site, not even half of it (approx. 15k products).
In the audits done online with free tools, the results are very contradictory. Some say that it is a problem of canonical, nonindex, redirect 301, http,there is no ga4,…others see them as normal.
I personally do not find any of these.
The site spent some time in the redesign, with the option “discourage search engines…”
Either there is a conflict or I did something wrong.
I would appreciate your help, please, because after a lot of work I seem tired, and maybe I don’t see simple and logical issues.
Before the redesign, I had 300 products, which were indexed without problems, very well and quickly, RM helping me to quickly get where I wanted,…now…
Thank you.