Fixing a massive traffic drop after rebranding

This is,absolutely true .Rebranding is the same as,pivoting so when businesses do make that move it shows that their business IQ is high .

Brand search is a strong signal, it's very important that people start searching for the new brand rather than the old. Extra marketing making sure that the new brand searches overtake the old brand searches is imperative!

If you're launching a completely new site design with the rebrand, it's gonna take a long time to recover, if you recover at all. Even if it's done incorrectly, a lot of customers who trusted the past brand will drop out.

rebranding is completely showcasing your brand as a new brand with addition to some quality features in the previous one and the product in the whole process remains same.
There are some pros and cons for rebranding
Although it has a lot of benefits but it also come with a lot of challenges
To encounter these challenges you should goes with specific approach
Some issues for sudden traffic drop are as follows:
Site structure and site copy, redirection destablization...
If your traffic dropped as a result of one of the issues above, you should make it a top priority to remedy the problem as soon as possible. That being said, your traffic likely won't come back overnight. It may take a few weeks for Google to crawl and re-index all of your new pages, and until they begin ranking in search results again, your traffic will be lower than usual

That's true. Changing a domain name (and, consequently, a brand/site name) is a complex and risky process. However, the risks of losing organic traffic can be minimized if everything is done correctly.

At our agency, we follow a three-stage website rebranding process:

1. Creating an exact copy of the website - Everything, including the content, website design, URL structure, and other elements, remains identical, except for the new domain name. Essentially, the only difference will be the domain and the presence of your new brand name on the website.

2. Setting up page-by-page 301 redirects from the old domain to the new one. All old pages need to be redirected to their corresponding new versions as quickly as possible - immediately after launching the new website. Speed is truly crucial here.

3. Once keyword rankings have stabilized and organic traffic has fully or almost fully recovered, you can proceed with redesigning the website if necessary as part of developing your new brand. However, I strongly advise against changing the URL structure of the website to avoid losing search traffic.

That's the general overview.