The evidence
Imhotep is exceptional because the connection between the name and the building is not a later tradition. An inscription naming him appears on a statue base of the king Djoser found at Saqqara, with titles including those of a high official and overseer of works. That is contemporary documentation of the kind almost no ancient architect has.
What the inscription does not do is describe his role in design. The inference that he was the architect of the Step Pyramid is a reasonable one, drawn from the titles and the association, and it is an inference.
The building
The Step Pyramid at Saqqara, of about 2670 BCE, is the earliest large-scale cut-stone building known. It develops from a mastaba by stacking six diminishing stages, and it sits within an enormous walled complex containing dummy buildings — structures with solid interiors that imitate in stone the reed and timber architecture of earlier practice.
That translation of one material's forms into another is the most interesting thing about it, and it is visible in the fabric.
Deification
Imhotep was venerated after his death and eventually deified, associated with medicine and wisdom, and identified by the Greeks with Asclepius. That later cult is well attested and is a fact about Egyptian religion over two millennia rather than about the man.
Nothing securely connects the historical official to medical practice. The association belongs to the god he became.
Why this platform records him
Because the pairing of a named individual with a standing building is so rare in antiquity. Most ancient architecture is anonymous, and the few names that survive — Iktinos, Mnesikles, Sostratus, Apollodorus — are mostly known from later literary report rather than from contemporary inscription. Imhotep is the outlier.