The right to fork the software is at the heart of open source. WordPress itself started as a fork of the b2/cafelog project. WordPress was one of several forks from b2, which included b2++ (which eventually became WordPress Multisite) and some like b2evolution which still continue today.
The last decent fork attempt for WordPress was ClassicPress in 2018, over disagreements about Gutenberg being integrated into core.
We’re very proud to announce that Vinny Green, a former WordPress community member, has started his fork, FreeWP. We strongly encourage anyone who disagrees with the direction WordPress is headed in to join up with Vinny and create an amazing fork of WordPress. Viva FreeWP!