How to solve the situation with improvements?

Question

Freelance

A couple of years ago, my friend made a site on OpenCart for 5k rubles.
Now the time has passed, a person wants to run an ad on the site. Someone audited the site and said that for advertising (or SEO promotion, I don’t know for sure) you need to make corrections to the site.
Over 20 items. Starting from removing duplicates h1, removing unnecessary tags, sitemap, alt, title, micro-markup, etc.
Why didn't I do it in the first place? - I did not know all these points (little experience). But I did the task of making a website, everyone liked everything.
Now the question is, what would you do if you were in this situation?

• Complete all these 20+ items (of course for free).
  
• Run basic (https connect, sitemap, etc.)
  
• Or just give up on it?
  

Answer 1

The site performed the task for n years and satisfied the customer. What is the problem in general?
New requirements - new order.