The zipped file I downloaded via phpMyAdmin is just 90kB?

That maybe fine (90 posts isn’t that much database space) but for comparison try installing a backup plugin, back up and download your database and compare the file sizes.

If they’re about the same then you are probably fine.

https://www.ads-software.com/plugins/search.php?q=backup

Make sure you also backup your files as well. ??

Thanks. One more thing before it’s resolved. Would I just upload this mere ”database” and all my stuff will come back? (Suppose on a new host)

No, the database is only one component in a WP site. Obviously you need the WP core files but also the wp-content folder, which contains theme files (style/page templates etc) and asset files like images. Only when all those things are put back in the right order will your “stuff come back”.
The database’s role is to store connections to assets like images, not the files themselves.

But say if I install WordPress on another host, so I’ll have to upload only the wp-content through the FTP. And on the host’s cPanel, I’ll have to upload the database, which will connect the actual physical files to the WordPress website, right? The content folder and this database is all I need?

You may also need the plugin folders at the version they were at from prev site and any folders that may have been created in root. And, one does not upload a database. One would Import a database. Review Moving WordPress.

This has a pretty complete explanation:
https://codex.www.ads-software.com/Moving_WordPress

Thanks

Uh wait. It says

If you are changing to a new server but same domain, all you need to do is edit wp-config.php with your new database/user information and upload everything as it is to your new server.

in that guide.
Now, “upload everything” means what? The entire .htdocs folder?

In that scenario, yes. Install WP, transfer the existing wp-content folder, import the db and adjust wp-config to match new db credentials.

Thanks, that solved the problem.