I could say your ranking drop was likely due to the 5-10 days of downtime, causing search engines to reduce trust in your site. To recover, focus on reindexing through GSC, improving content and on-page SEO, and building high-quality backlinks while removing toxic ones.While relocating the web/DB server, access to the site was not smooth for about 5~10days.
This was 3-4 months ago.
Consistently optimizing and monitoring performance should help regain rankings over time.