I need some guide, can't fix: 1.28K of your pages aren't indexed: Server error (5xx)

Hello everyone,

I have been trying to fix this by myself on my website, but after months of trying and lot's of work, test and frustration I have no choice but to ask for guidance here because i am hitting a wall...

So I have this website where I keep getting this error:

1.28K of your pages aren't indexed: Server error (5xx)

Some context of what I did.

• Removed all subdomains I had because I did not need them anymore.
• Update my sitemaps on google search console
• Updated all my keywords
• Check if I have Canonical, and I do have
• Added a ld+json schema in all my pages
• Added all the meta tags
• Sitemap is updated and asked to be crawled
• was wondering if this has to do with where I host my website, Netlify.
• Made 100s of tutorials
• Added a blog
• Remove all my redirects because I do not need them anymore

My question is, if there's anything you would recommend doing?