change domain after install rankmath

I have a website I am building on a subdomain called test.mywebsite.com
(That is not the real URL but you get the point).

The website test.mywebsite.com is a completely rebuild version of mywebsite.com
mywebsite.com is built with Joomla and does not have any SEO setup.
Also, all the link structure on mywebsite.com is a mess so I changed all the permalinks on test.mywebsite.com

I am just concerned about losing SEO points at google so I have to make all the redirections in “RankMath redirections” so the old permalinks get redirected to the new permalink.
And I should do this before I move my new website from test.mywebsite.com to mywebsite.com right?

But is it a problem to install RankMath on my new website while it is still called test.mywebsite.com or should I install RankMath when I have moved the new website to mywebsite.com?
I don’t know if I will get errors in RankMath when the domain of the website changes from a subdomain to a main domain.

Do you have some articles about what to do to make sure RankMath still works when a website is moved to another server or another domain?