There are several ways to rename a Site Collection in SharePoint:
A quick overview of these three with the advantages/disadvantages you can find on Technet.
And of course (if you have) you could use such tools as ShareGate…The article or information provided here represents completely my own personal view & thought. It is recommended to test the content or scripts of the site in the lab, before making use in the production environment & use it completely at your own risk. The articles, scripts, suggestions or tricks published on the site are provided AS-IS with no warranties or guarantees and confers no rights.