Where to do a redirect if the site no longer has services?

Question

Search Engine Optimization

Hello!
The following situation happened: the site was divided into two and part of the services went to the new site, and part remained on the old one. In this regard, the old site has a lot of pages giving 404 errors. What do they usually do with it? Redirect to a new site? Or just wait until they fall out of the index themselves? Could you tell me, please, what is usually done in such situations?
And on the old site there were articles, the uniqueness of which did not exceed 10%. What to do with such articles? Transfer as is and throw a redirect on them. Or rewrite taking into account the occurrence of keywords and with uniqueness of 85% +? But at the same time, while the article will be compiled with technical specifications, while it will be written, etc. it can fall out of the search and then, probably, everything will be in vain?

Answer 1

Do a redirect to a new site, what's the difference with the index if you lose customers?

Answer 2

I do not recommend doing a redirect!
Return the page with the service and write "Unfortunately, this service has been moved (and a link where)".
Why can't you do a redirect?
If I understand correctly, you moved individual services to another domain, and redirecting from one domain to another already smacks of a forced transition of the user.
Clear the meta tags and the page will eventually cease to be relevant, and its trust will go to a new page of the new site. Over time, the old page will no longer be relevant, it will be replaced by a new one.