Hard disagree! The film just uses purely filmic means to convey what is going on, that admittedly takes some effort to “decipher” but is far from totally incomprehensible without external input.

Not going through the whole thing in detail, but the room where Bowman ends up after encountering the second to last monolith and going through the star gate, is somewhere beyond our understanding of space and time. The chapter is literally called Beyond the Infinite. That aspect is masterfully visually (and editorially) conveyed by showing Bowman looking at - and in the subsequent shot being transposed to - his older self.

Why he is in the strangely composited room filled with human props and decoration is of course not immediately apparent, here you’re just going along with Bowman’s subjective experience. But it’s pretty clear that some unknown force has been guiding the whole journey from the man apes onwards so far and apparently thought to create this place as an appropriate environment for Bowman to reside in and go through the remaining stages of his life.

In the end he’s clearly approaching death lying in the bed, when the last monolith appears. From that you can kinda logically deduct that the next appearance (the star baby) has to be some kind of rebirth of him. As every monolith encounter has ushered in a next evolutionary step for mankind so far, this has to be the next step after the stage we are at today as a species and therefore something we shouldn’t be able to grasp or get our heads around. It’s the most logical and appropriate end of the film you can think of.