Of course everything based on Chromium will inherit most of Chrome's decisions, including this one. (Unless they fork their entire web extension implementation and maintain the fork forever.)
Safari isn't exactly non-major. By the way, it seems like WebKit Embedded (~resource-efficient Linux port) has regained some steam due to Igalia's work over the last two years or so.
Non-Chrome Chromium browsers should band together and support request blocking for Mv3 at this point. It would be one compelling feature that differentiates them from Chrome.