It is. Make no mistake, that is exactly what happened here. You don't build up the main villain of the next saga only to then pivot into a different one near the end of said saga. Them screwing up Kang along with Jonathan Majors' actions are what led this to happen, bringing in Doom was never in the cards originally.
It is nothing but a shameless desperate move from someone who's trying to regain the goodwill he once had when his franchise has been struggling quality and money wise these past few years. This was not due to some brilliant creative idea or story they want to explore, it's about playing it as safe as humanly possible and bringing back the beloved actor who helped kickstart the MCU. The fans did not matter to Feige in this decision, only the general audience's wallet, otherwise we finally would have gotten a faithful Doctor Doom adaptation in a Fantastic Four sequel down the line. This is more apparent when we have now learned that Matt Shakman, the man tackling the MCU Fantastic Four, had absolutely no input in the casting of Doom