While the built-in debugging options in WordPress should cover most of your needs, there are a number of plugins that can help you with debugging your code.
You can find these plugins in the WordPress Plugin Directory by searching for “debug” or “debugging“.
Two of the most popular options are Debug Bar and Query Monitor.
Debug Bar
Debug Bar is a plugin built and maintained by the WordPress developer community. It adds a debug menu to the admin bar that shows query, cache, and other helpful debugging information.
When the WP_DEBUG constant is enabled, it also tracks PHP Warnings and Notices to make them easier to find, and when SAVEQUERIES is enabled, the MySQL queries are tracked and displayed.
Query Monitor
Another option is Query Monitor, which also adds a debug menu to the admin bar and displays information about the current page request.
Query Monitor enables debugging of many things, including database queries, PHP errors, hooks and actions, block editor blocks, enqueued scripts and stylesheets, HTTP API calls, and more.
Summary
Both plugins are great options for debugging your WordPress code and can help you track down issues more easily.