Regarding your question, nofollow backlinks, including those from PBNs, don’t directly pass link equity to your site, but having too many spammy links, even nofollow ones, can still hurt your overall trustworthiness in search engines.
Here’s the breakdown:
Spam Score Impact: While Moz’s spam score doesn’t directly affect rankings, a high concentration of backlinks from sites with spam scores in the 10-40 range can raise red flags. Search engines might view your site as risky if the pattern seems unnatural.
Competitor Strategies: Some competitors might be getting away with PBNs or spammy links now, but this is risky. Algorithms like Google’s Penguin are designed to catch such tactics, and penalties can follow.
What You Can Do: Focus on acquiring quality, natural backlinks from authoritative sources through guest posting, content marketing, and relationship building. Also, review and clean up your link profile regularly—use Google’s Disavow Tool for any toxic links that could harm your SEO.