Pass value into a view using block input
Not answering directly, because I don't know if you could do this with a configurable Views block without custom code.
A different approach only using UI would be on entity level, creating a block type containing two fields, the taxonomy drop-down and an EVA field passing the other field's value via a token. The site admin has then to use the Custom Block Library to create a custom block for this block type.
Add the EVA field to the block type with this module: https://www.drupal.org/project/eva