What I know is that the more effective is to link a page, post, product or something on your website not the main URL. Because it will be recognized when the crawler on Google fetch the other site it will see that is different links not the same and that counts more as multiple redirects if you just target the main URL or one specific URL 500 times even from 500 websites it will just count as one for your website. And the domain authority will not rank just like that just one link from a good authority's website targeting to your site and you targeting to another good authority website. Will start ranking your domain. You can have a billion links from around the world and that is not giving any porcent of authority to the domain. Because for the crawler algorithms it look like not legit.so, what the best strategy to use?
For example, i have main site and second site that push main site like PBN
is that good to add backlink for my main site? or i just used it to my second site?