What websites do you use for buying backlinks

My website currently has an SEO score of 83%, but despite that, I'm not ranking on Google search results. After using the free version of Ubersuggest to compare my site with competitors, I discovered the issue: my competitors have numerous backlinks, while I have none. I explored Reddit for advice on building backlinks, but most discussions focused on organic methods and guest posting without offering clear guidance on how to obtain backlinks.
At this point, I'd prefer a faster approach by purchasing some backlinks to give my site a boost and help it rank on the first or second page. This way, I can start gaining organic traffic. My question is: where can I buy legitimate backlinks from well-established, high-ranking websites without raising any red flags with Google?
I've checked Fiverr, but most sellers charge £20+ for a single backlink. Any advice or recommendations would be greatly appreciated, as this issue is impacting my website's growth.