I'm a little confused. Of the commits linked which seem to be the "breaking changes", two seem to be entirely documentation updates that are 90% changing the title casing.
The remainder seem to be around updating the pipeline/other files to specify support for php 7.2-7.4 instead of 7.4+8.0 and a bunch of other documentation (phpdoc) changes.
October 2.0 was based off of the code base as of a year ago, so everything that was added to the project in the past year was removed in 2.0. As far as breaking changes in the 1.0 & 1.1 branches go the links are mostly talking about the docs changes that indicated the removal of the recent changes; but there are some that actually cause problems for current projects that aren't upgrading, such as the removal of the wikimedia-merge-plugin which is required for plugins to load their dependencies smoothly.
The remainder seem to be around updating the pipeline/other files to specify support for php 7.2-7.4 instead of 7.4+8.0 and a bunch of other documentation (phpdoc) changes.
What are the drastic breaking changes thusfar?