If you want proper SEO, forget that useless online SEO audits. Most of SEO problems was already discussed on GitHub but none of them will be fixed soon.
To name some arround:
- Slug traslitearion.
- Redirections.
- Duplicated metadescriptions.
- Optimize internal links.
- Optimize HTML headers.
And i'm sure that exists much more to fix but... surprisingly SEO is not a priority for developers. At the moment you can expect traffic loss and be uncompetitive in Google rankings.