Octopus merge will fail if there are any conflicts that require manual resolution [0], but there are ways around this like manually creating the commit. Raymond Chen had a has some interesting posts using this to split files while preserving blame history [1] (the manual method is linked at the beginning).

0: https://git-scm.com/docs/merge-strategies

1: https://devblogs.microsoft.com/oldnewthing/20190918-00/?p=10...