Fun story. I helped someone with a wordpress site recently where I provided an internal address for development. Once they were done with development I moved the site to the public url and found that most of the pages were broken.

Turns out multiple plugins make changing URLs a feature behind a monthly paywall as a monetization strategy. The sobering thing is that the fix is to update tables in the database. There are various examples in github for these things, however most people just use a plugin that literally does a find and replace for the old URI and replaces with the new. Frightening...