Strange looking backlinks that all my competitors have

So I've been learning the fundamentals of SEO over the past year or so, and I recently started to actually build websites to put what I've learnt into action. I now have a site that has all the main pages built, and I want to start building backlinks

Using my top 4-5 competitors' URL's, I've used Semrush's Backlink Gap tool, so I can try to get some of the same backlinks that they have. However, they all seem to have these strange looking backlinks that have uncommon TDL's such as .td or .hu or even .ne.jp

When I click on these sites, it takes me to what looks like an SEO agencys website and backlink buying sites, and the actual link/anchor text that is meant to be going to my competitors site, is nowhere to be seen on their site. Sometimes it just sends me to an expired domain or an error code pops up instead of a site.

Two Questions: 1: What on earth are these backlinks and how does it work that if I go to the page, I cant even see the backlink back to my comptetitor. and 2. Are these backlinks that I should try to get? (even though I dont know how to get it because the site is not a normal blog or webpage)

I'm just assuming these are backlinks I should go for, because either all, or most of the sites actually have the same backlinks from those same strange sites, and these are the competitors who are actually ranking at the top of google for my keyword so it must be working right?

Thanks in advance for any advice!