paulosebin,
Welcome to WebmasterWorld [webmasterworld.com].
I've exemplified your domain name, not because it might not be relevant, but because leading members to your site, either via linking or by name or keywords, is not permitted in the public areas of WebmasterWorld.
Before deleting the domain, though, replacing it with "example.tld" (which is a domain name designed to be an example domain)... I did search for your brand name as it was in the domain by itself (ie, as before I replaced it with the word "example"), and Google does return your site in first place. This suggests to me that it hasn't been "banned"... ie, it's still in the index... but it might not rank well on competitive queries for a variety of reasons.
How low it's doing in competitive rankings, though, may have to do with Expertise, Authority, and Trust... which might include, eg, how trusted your material is, or how original it is. I did not look at your site, though, and your niche is something that our Terms of Service allow us to discuss only in the very broadest terms.. ie, no specifics to lead to your site. .
I posted a few thoughts on an earlier thread, about how I believe subject matter "niches" are becoming more and more granular, with subcategories that effectively "intersect" these "EAT" categories in different ways. This might apply to your current situation, and might explain the drop....
Updates to Google Search Quality Raters Guidelines on Sept 5, 2019 9/10/2019
https://www.webmasterworld.com/google/4963546.htm [webmasterworld.com]
Or, another possibility... you may still simply be targeting keywords, but, increasingly, the new Google algos are all about concepts.
The idea of "relevance" gets complicated in all this, and includes many more factors than keyword matching, and exact keyword matching has become de-emphasized.