Best choice for backlinks

My eCommerce website has a little organic traffic in a no competition niche. My competitor is ranking #1 for a main keyword (700 searches monthly) and 11 long tail keywords in the #1 spot. All the keywords add up to almost 4K monthly searches. In the top 10 his website is ranked, his FB page, and some of his inner pages.

According to Ahrefs his UR is 21 and DR is 10. I checked his 100 backlinks and they are low quality. His main keyword is in his URL. The main keyword difficulty is 8.

What would be the best choice for white hat backlinks? High authority guest post?

Thank you!

The best way is to combine types of backlinks. Follow competitor's strategy and do guest posting.

But to do it without a good content will be harder, mind that behavioral factor still matter.

Guest post, PBN, web2.0, press release... Contextual backlinks from good authority domains, using relevant articles.