Back in the day I had several subdomains to the same domain to my site in an effort to boost performance SEO-wise. Now when I look back, it seems that putting everything in one domain results in faster performance which is even better for SEO.
What I have done months ago is removed all my subdomains from all webmaster tool accounts registered to my name and I also removed relevant verification files from my server document root folder for each subdomain.
I checked my logs recently and notice that requests are coming in to one of the subdomains.
I think there's a disavow tool in GSC (google search console) but is there a way I can use something like that on subdomains without having to re-register each of them into GSC again? and is there a similar procedure I can follow in yandex and bing (without re-registering my subdomains)?
When this process is done, I want it where in the future, no search engine will ever make a URL request containing any of the subdomains I asked to be removed.