Changing Hostname

I am slightly confused by the following information because no emphasis on which is the best method to change the site URL/hostname.

When I go live, I will be changing the hostname(domain name) on the server, but not moving the files. So the box will be changed from example2.edu (development) to example.edu (production).

I am trying to figure out the following page which presents several options, but does not really suggest relevance and differences and or best method:
https://codex.www.ads-software.com/Changing_The_Site_URL

Do I need to change in wp-cofig:
WP_SITURL
WP_HOME
More info:
https://codex.www.ads-software.com/Editing_wp-config.php#WordPress_address_.28URL.29

and then follow Relocate Method:
https://codex.www.ads-software.com/Changing_The_Site_URL#Relocate_method

Do I need to edit functions.php:
https://codex.www.ads-software.com/Changing_The_Site_URL#Edit_functions.php

Do i need to change the URL directly in the database:
https://codex.www.ads-software.com/Changing_The_Site_URL#Changing_the_URL_directly_in_the_database
and or:
https://codex.www.ads-software.com/Changing_The_Site_URL#Domain_Name_Change

Maybe we should not have a hostname for the website, while in development so when we turn IP address live (production) and apply https://example.edu to server, wordpress will not need updating. However, I do not want to develop links with IPs because these will not be usable to our users.

Any insight would be helpful.

Here are some additional potentially helpful info links:
https://www.velvetblues.com/web-development-blog/how-to-move-a-wordpress-blog-or-website/
https://www.seoblogr.com/social/how-to-move-wordpress-blog-from-old-domain-to-new-domain-with-301-permanent-redirection/
https://www.mydigitallife.info/2007/10/01/how-to-move-wordpress-blog-to-new-domain-or-location/
https://codex.www.ads-software.com/Giving_WordPress_Its_Own_Directory
https://codex.www.ads-software.com/Moving_WordPress
https://codex.www.ads-software.com/Editing_wp-config.php#WordPress_address_.28URL.29
https://www.ads-software.com/extend/plugins/domain-change/
https://silentbits.com/wordpress/howto-change-domain-blog/
https://yoast.com/move-wordpress-blog-domain-10-steps/
https://www.tamba2.org.uk/wordpress/site-url/
https://www.ads-software.com/extend/plugins/search-and-replace/

Thank you.