[Help Needed] Website remade, had a severe traffic drop

Backstory:

My friend’s site is in some sub-niche of the tech world, she has been doing pretty good: 600 users/day (80% google search traffic + 15% direct + 5% referral) at a steady pace with the effort of merely providing original content.

Here comes the change: 2 months ago she decided to rebuild the website, with the idea of doing onsite seo to boosting the traffic, the stupid web developer who remade the site abandoned (no page entrances on the new site) nearly half of her ranked pages and the other half had completely broken CSS that looks like shit.

According to GA, her traffic (mostly search traffic) began to drop since the day the newly-made site’s launched.

Up until now, 4 months after the relaunch, she has a search traffic decrease by 70%, direct traffic 40%!

Tldr:

site’d been doing well,

decided to make it more user-friendly,

reconstructed by a moron who put zero consideration into SEO.

traffic dropped very badly since the relaunch

the site’s nearly dead by now

Question:

What is the fastest way to get those dropped pages back into ranking? Will it work by putting them back on the relaunched site and linking them on the homepage and high PA pages?

Or should she just switch back to the old version of the site and wait for it to regain authority?

Does anyone have a similar situation?

did you move to another domain? Did you change the URL structure? is there anything preventing correct indexing like robots.txt, meta robots instructions? there are too many questions if we don't see the site.

gregz06 said:

did you move to another domain? Did you change the URL structure? is there anything preventing correct indexing like robots.txt, meta robots instructions? there are too many questions if we don't see the site.

Click to expand...

Problem solved bruh.
URL structure was partly changed, there were nothing in robots.txt preventing googlebots from indexing.
How I found and fixed the issue was fucking hilarious...
Anyway, she's bout to rebuild this se-unfriendly site for a third time pretty soon...