Categories as subdomains

Hi, I’m not a tech, but I want to have my categories as subdomains, and I can’t realise how to do it with .htacces.

I have the standard .htacces for pretty permalinks.

Categories:
https://www.domain.com/category1
And I want to have:

category1.domain.com

And for the articles I have:

https://www.domain.com/category1/date/post-title

I would like to have:

category1.domain.com/date/post-title

I already have a lot of indexed pages (including categories and articles) and I want to redirect them with a 301 because I don’t want to loose them.

Thanks in advance.