What phone should I upgrade to?

I currently have the s21 base model and i like it more than the newer series and i was thinking about getting the s21 ultra. However, as one ui 7 is going to be the last major update from what I heard, i was thinking about upgrading to the s23 series and heard the s23 fe would be closest to the s21 in design? Or if it's possible to buy the s23 ultra. What would be recommended if I can't buy the s23 ultra?