I need changes made to my website,

I am looking for someone to fix the website for my business Workplace Connect. The issues that need fixing are as follows:
- 43 internal links are broken – most of these are one issue which is a template page (which is private) showing up as an internal link for all webpages
- 2 pages are returning a 4XX status code
- 1 page has a broken canonical link
- 42 pages have a low text-HTML ratio
- 42 pages have a JavaScript and CSS total size that is too large

I also require additional fixes as we develop the website and ensure it is optimised for mobile and desktop.

I am looking for this to be fixed as soon as possible because the website is live.

Thank you