Sorry but there is a One UI7 update coming for S24 Series.
It is currently in beta (I am using it) and it is expected to be released in February for S24 devices.
At the end of the day, Samsung manufacture and sell devices. So it is very logical that they will give their newest and arguably best devices first shot with older devices following.
Also note that Samsung now give 7 years updates on S Series and A series are seeing longer update policies too which will bring them bm broadly in to line with IOS.
Or are you simply complaining that you don't have One UI7?
S24 Ultra