Yes, there are techniques for automatically changing all internal links from http to https. If you're using a content management system like WordPress, one option is to use a plugin. The 'Better Search Replace' plugin, which is one of the most popular plugins can help you with this. As, you can replace all instances of http with https in your database, even internal links.
If you're using WordPress, you can also utilize a command line tool called 'WP-CLI'. WP-CLI includes a 'search-replace' command that may be used for substituting all instances of http in your database with https.
If you aren't using a content management system (CMS) like WordPress, you may utilize a search as well as replace tool like 'Notepad++' or 'Sublime Text' to substitute all instances of http with https in your site's files.
Regardless of the approach you use, you should always back up your site before implementing any big changes to your database or files.