Using PR sites for backlinks can be a good strategy, but keep in mind that many press release distribution services delete links after a set period typically 3 to 6 months. Some archive them indefinitely, while others remove them, meaning the backlink may not be permanent. Moreover, most PR sites provide nofollow links.
Of course it adds value to your SEO but short term. So focus on building evergreen backlinks through guest posts, niche edits, and editorial features on authoritative sites that don’t expire. However, this approach requires a healthy budget for quality placements.