Can’t update WordPress

My last paragraph relates to converting a staging site to production, regardless of how staging came to be in the first place. Altering hosting settings so domain requests go directly to the subdirectory where staging currently resides is one option. Or you could reconfigure the current production site’s wp-config.php to use the current staging DB. You’d also need to copy over any newly introduced files in staging’s /wp-content/.

Either way, all the URLs in the staging DB need to be updated using the Better Search and Replace plugin.

Altering hosting settings is probably slightly easier, but some people don’t like their main production site in a subdirectory, they want it to be in public root (/public_html/ on many hosted servers). What to change varies by host. Whatever UI is used, what in effect happens is a virtual host file is set up to direct domain requests to the subdirectory. From the outside, there’s nothing indicating the site is in a subdirectory and not in public root.