Organic Traffic Loss - Waiting for Comments from SEO Experts

[eyes]

Hello, I have a small WP blog named antreman.net that I opened 9 years ago, which contains fitness and nutrition information. Despite not updating or adding new content for years, the site used to receive daily 4-5k unique visitors and 15k page views. Due to some errors, I lost these numbers. I will summarize my mistakes and look forward to your advice. I was hosting the site on OVH servers, but in March, OVH servers had an accident which caused my site to crash. I rebuilt the site on another server by importing the backup of the posts a few days later. However, the problem started here - I accidentally left the date part in the URL structure of the new site's permalinks! As a result, the new site's URLs were indexed with dates in Google and mixed up with the old links (resulting in many 404 errors). When I realized the issue after some time, I removed the date from the permalinks, edited the sitemap, but it was in vain - once the damage was done. Additionally, as I lost indexing, cheap sites copied my original articles by copy-pasting, making them appear as "duplicate" on my site now. I spent weeks fixing the site from scratch, updating the posts, adding new ones, conducting audits on Semrush to fix my mistakes, etc. However, nothing worked; for 2 months I've been struggling to get only 500-600 organic traffic, and there is no sign of the site reaching its former strength. The domain authority score dropped from the 50s to 20s. Seeking advice from experts, what would you recommend I do? Thank you.