Anil Sardemann

This plugin distinguishes between block and non block themes to add a fullscreen background image to WordPress. It is set either to the body tag (in case of a non block theme) or to the wp-site-blocks class (in case of a block theme). Upload an image or choose one from your media library. Simple plugin that allows you to set a background image for your website easily.
<a href="https://playground.wordpress.net/?plugin=custom-background-image" title="WordPress Playground Demo" rel="nofollow ugc">Demo</a>

Custom Background Image

Simple plugin that allows you to set a background image easily. Upload an image or choose one from your media library.

Demis Patti

flavor

cbParallax lets you add custom background images with a vertical or horizontal parallax effect to your WordPress site. You can set a single background for the entire site or configure individual backgrounds for each post, page, or product.
Features:
<ul>
<li>Background image with smooth parallax scrolling effect</li>
<li>One image for all pages or individual backgrounds per page/post</li>
<li>Works vertically and horizontally</li>
<li>Various overlay patterns to choose from</li>
<li>Color overlay with opacity control</li>
<li>Boxed layout option with customizable margins</li>
<li>Mobile device detection with option to disable parallax on mobile</li>
<li>Compatible with WooCommerce products</li>
</ul>
Requirements:
<ul>
<li>Your theme must support the WordPress <a href="https://developer.wordpress.org/themes/functionality/custom-backgrounds/" rel="nofollow ugc">Custom Backgrounds</a> theme feature</li>
<li>For parallax effect, images should be at least 1920px x 1200px</li>
<li>PHP 8.0 or higher</li>
</ul>
<h3>Privacy Policy</h3>
This plugin does not collect, store, or transmit any personal data. All settings are stored locally in your WordPress database.

cbParallax

Custom background images with parallax effect for posts, pages and products.

Custom Background Image vs cbParallax