Drupal's block module is limited by the fact that a block can only have one instance. Each block has a 1:1 relationship with its region, weight, visibility (and other) settings. This means that it is impossible to have blocks in multiple regions or to have blocks that have different settings on different pages.
MultiBlock module solves this problem by allowing you to create multiple Block Instances of already existing blocks. Please read the README for more information.
There are discussions about including the functionality this module provides in core, however it appears to have been pushed back until D9, see #430886: Make all blocks fieldable entities