The keyword I need for seo is "cua nhom xingfa". But when I search, I can't find my website on google. Even though I have backlinks and links on my website. Even if it's outside the top 100. What did I do wrong?

Hi guys, I'm currently seo this website

nhaxinhdoor.com

It's been 2 years since Seo, but I haven't been to the top key Going to buy seo on backlinks az or something, buying newspaper backlinks is not good Please advise me Thank you guys