I know that this is a recurring question but still haven't got a real answer
I have s21 ultra on three network /Sweden (i think this goes to UK as well)
Three pushed out June update supre late and now still waiting for July's
If you compare this to firmwares that pushed ( three network ) out for the s20 and note20U you will find that three pushes OTAs at approximately same time as everyone else
Is there something wrong with three and s21 series?
Hope someone can explain
Since it is carrier branded firmware, they are just slow at certifying it for release by Samsung.
Typically a network wants to test software before allowing Samsung to push it out so that they can test that nothing within it clashes with their network apps and features.
I would suggest to take a look on your particular networks support page's for a Firmware Statement and also look on their official Forum to see if their are any similar posts similar to yours.
I wish you all the best with this.
Current Phone > Samsung Z Fold³ 5G.