I got the update to ui 3.0 ota from O2 today, and as I noticed when my s10+ had the beta of ui 3.0 my WiFi speed has dropped.
Where from my chair I was getting 1.08 to 1.2 Gbps before the upgrade I now after the upgrade get only 864 Mbps from my chair this is the same sort of performance drop I saw on the s10+ before switching to the s20 ultra 5g, and now I have the same problem after updating to ui 3.0
Worldwide, there are some 150 different firmwares for your device, both carrier branded and unbranded. It all depends on your CSC code. There are 5 different CSC codes for the U.K. alone for your model.