The core Media and Text block is a compound block featuring an image on one side and a paragraph block on the other.
Using dynamic sources for the image breaks the block.
This broke with WordPress 5.9 and remains broken.
This is proving tricky to resolve. In the meantime you can achieve a similar output by instead using the core Columns block to insert 2 columns, adding an image block to one column and a paragraph block to the other. To match the output of the Media and Text block you may want to choose middle for the vertical alignment.