Broken Styles After Site Migration in wordpress 6.1 and Later

Bottom line: using a Block Theme caused the styles to go missing.

Background

I wanted to migrate from the BaoTa panel to 1panel, which required migrating my wordpress files. I followed my usual migration process.

1. Migrate the website directory
2. Migrate the database

1panel has a few quirks, so the full process was:

1. Create a new site, still using a php runtime environment
2. Copy everything from the test1 site's index directory to the test2 site's index directory
3. Keep using the original test1 database, which already had the data imported
4. Set the user and permissions under Configuration - Website Directory
5. Open the test2 site

Solution

Don't import the database; importing files is fine.

Export and import pages and posts using wordpress's built-in xml export/import feature.

Other styles need to be tweaked manually