Khokan Sardar

WordPress full-site-editing structure — patterns, templates, template parts, global styles, and navigation — lives in the database. Moving some of it from staging to production today means either a full database sync (which is destructive to production-only data like orders, users, and form entries) or tedious manual copy-paste.
SiteCargo packs exactly what you choose into a portable, reviewable bundle and applies it to another site with stable identity, ID remapping, and media handling — never touching the data you didn’t select.
It is currently a WP-CLI tool (an admin user interface is on the roadmap).
<h4>How it works</h4>
<ul>
<li>Export the entity types you choose into a self-describing bundle (a folder containing a manifest, one JSON file per entity, and the referenced media).</li>
<li>Diff a bundle against a target site to preview exactly what would be created, updated, or left unchanged — without writing anything.</li>
<li>Apply the bundle to the target: standalone posts (patterns, navigation) are matched by a stable identifier so re-applying updates the same item instead of duplicating it; templates, parts, and global styles are matched by theme and slug. Numeric IDs baked into block markup (images, reusable-block and navigation references) are remapped to the target site, and referenced media is imported and de-duplicated by content hash.</li>
</ul>
<h4>Supported entity types</h4>
<ul>
<li>Patterns (<code>wp_block</code>)</li>
<li>Templates (<code>wp_template</code>)</li>
<li>Template parts (<code>wp_template_part</code>)</li>
<li>Global styles (<code>wp_global_styles</code>)</li>
<li>Navigation menus (<code>wp_navigation</code>)</li>
</ul>
Only templates/parts that have been customized in the database are exported; unedited theme-file templates already ship with the theme.
<h4>External services</h4>
This plugin does not connect to any external service, send any data off-site, or phone home. Bundles are plain files on your own server that you move between environments however you like.

SiteCargo

Selectively promote WordPress full-site-editing structure and content between environments — without a full database migration.

Alan Fuller

The new generation og WordPress themes are known as Block Themes, sometime referred to as Full Site Editing (FSE) or Gurenberg Themes.
These themes disable the older customizer, on the presumption that all styling can be done via the editor.
Unfortunately this is not so, and some styles still need custom CSS if you want to perfect your designs.
There are several plugins that allow you to add additional CSS however there is no need to add another plugin as the ability is still within Core WordPress, in the form of the customizer.
All it needs is it to be switched back on – no bloat- just a switch and you can then access the customizer and add additional CSS.
This is a really lightweight plugin that adds back the customizer when hidden by block themes.
The customizer is useful for block themes mainly because of Additional CSS.
Whilst it is still available for block themes, it is hidden. This plugin simply brings back the links.

Add Customizer Back For Block Themes

Nice, simple, and does exactly what it says. 

It's getting the job done.

Simply adds back the hidden customizer for Block Themes such as Twenty Twenty Two and Twenty Twenty Three

SiteCargo vs Add Customizer Back For Block Themes