The linked Issue #8553 is "just" about creating a toggle for GPU acceleration. It's blocked by Issue #8552 [0], which is the actual Issue about the acceleration and originally belonged to Milestone "Release 4.3". It seems to have been removed later, which I didn't expect or know about. Accusation of lying was completely unnecessary in your comment.
Moreover, the Milestone was removed not because they changed their mind about the Release but for other reasons [1].
Ok, so your [0] shows that the real work has barely been started. The only indication it was ever planned for the next release was a misunderstanding on your part about the meaning of a tag that was applied to the issue for less than one day last fall, and they've stopped tagging issues with milestones to prevent such misunderstandings in the future. It still looks to me like your exaggerated claim was grounded in little more than wishful thinking.
Moreover, the Milestone was removed not because they changed their mind about the Release but for other reasons [1].
[0] https://github.com/QubesOS/qubes-issues/issues/8552
[1] https://github.com/QubesOS/qubes-issues/milestone/28
See also: https://forum.qubes-os.org/t/gpu-acceleration-development/24...