I can't replicate, can you please share if you have any console errors in the browser?

Confirmed.
Uncaught TypeError: this.querySelector(...) is null show http://localhost:8888/sample/joomla40/media/system/js/fields/joomla-field-media.min.js:1

in the non minified file
joomla-field-media.js:252:12

@infograf768 can you please enable debug to get the line number that throws the error?

this.querySelector('[role="dialog"]').open();

can you try this:

    show() {
      const button = this.querySelector(this.buttonSaveSelected);
      const modal = `imageModal_${this.input.id}`;
      const modalElement = this.querySelector(modal);

      if (!button || !modalElement) {
        throw new Error('Misconfiguaration...');
      }

      modalElement.open();

      Joomla.selectedFile = {};

      button.addEventListener('click', this.onSelected);
    }

build/media_source/system/js/fields/joomla-field-media.w-c.es6.js around line 194

To replace entirely

    show() {
      this.querySelector('[role="dialog"]').open();

      Joomla.selectedFile = {};

      this.querySelector(this.buttonSaveSelected).addEventListener('click', this.onSelected);
    }

??

yes, replace the whole show function

Uncaught Error: Misconfiguaration...

have to go. will be back later.

Please test #30455