How to get backlinks for extremely niche website ?

IPTV is a tough niche because most public link sellers are just peddling trash that gets wiped out fast, you need to peek at your competitors' profiles and see exactly which tech blogs or private networks they’re using to rank, focus on getting a few high-quality guest posts on sites that actually have real traffic instead of buying cheap bulk packages.

as a beginner i would like to focus on creating good content that people actually looking for.

If you’re getting the CTR and sales that I mentioned before, you don’t need any random PBN style links—what you need is relevant and authoritative links
Do your niche editing, outreach, and build some good linkables; in IPTV, quality links and good internal SEO will beat all those low-quality backlinks.

i would say update existing content regularly so it stays useful and worth referencing helps to get backlinks for niche websites.