Always update to new OS, that will give you added features and more security.

I hope you haven't done something with the software of the phone. If your phone is all original then you should have received the update by now. Switch off your phone for couple of minutes and the restart. If it doesn't work then try factory reset. I...

If you are using s25 then you should get it any time. Else you have to wait for few more weeks.

S25Ultra

18 September was announced initially. Should come within this month. It all there on Samsung official sites and Android platforms.