Not that they are bad phones, but the price differences with the Ultras were usually not enough to warrant decent sales numbers, so rumors started swirling that Samsung will deprecate the Plus line.
For comparison, the current Galaxy S24+ is denoted as SM-926, so if history is any indication, an SM-936 model number is a hint that an S25+ exists. Now, whether it will be released, and in which markets, or why is it not in the IMEI database still, are anyone’s guess.
Samsung is apparently still not ready to ditch its S line trifecta, and a thorough redesign or reshuffle of the series is only expected for the Galaxy S26 models.