How to set up a redirect from the old site to the new one?

Question

Search engines

Hello, the situation is as follows: a completely new site was created and placed in a directory to replace the old site. however, in the search results, of course, the links remained from the old site, so the following questions arose:
1. How to redirect all indexed pages to the main one? (Do not prescribe 301 redirects for everyone with handles?)
2. What about non-existent domains, they are not affected by htaccess entries. I understand that you need to create an alias *.site.ru and redirect them all to the main domain? and where to do it? in dns records to create a record of type A?
3. How to remove queries from the search results that no longer exist and will not exist? feed the map to Yandex and Google? or will it just happen on its own (won't it harm the site from frequent 404 page transitions)?

Answer 1

"do not prescribe 301 redirects to everyone with pens"
8,000 thousand pages were hacked by hand from a new site to a new one - the time of "manual rework" is several times cheaper than losing positions, losing money for project promotion, falling sales.
If there is no obvious way to make redirects through regular expressions, and indexes are important - do it with your hands.

Answer 2

Is the old domain still there?
you need to make the old domain an alias to the new domain. And write the correct host in robots.txt:
then everything will go smoothly