Not all but some problems can be fixed by a developer if you need this type of deep SEO & Technical SEO work. actually the things included in this file is for SEO & also some work of conversion rate optimization which I also understand and do but that will be a different thing and cost.
for speed optimization & coding stuff, core web vitals etc, either you can talk with your developer or we can try wp-rocket plugin.
What is seo
let me know what you think also thank you for sharing the keyword ideas. this offer is still valid if we stick to things I have shared otherwise we can setup another offer with all end-to-end SEO on-site and technical and conversion optimization.
How to do SEO
this comes with a bit higher price so I have only shared the basic things as you want for your client. thanks!