It's signal strength and to know if it's bad or not (will vary from carrier as well as location) you need to compare it to another device using the same network or SIM. Looking at your numbers though, it looks about right for 3. For reference here's mine from my S21 Ultra.
Thanks for the quick replies. I've looked at similar on the Internet, however I'm quite convinced that it is something to do with the Samsung device calibration not one if the usual standards. I have had numerous devices at this address, Xaomi mi5, Apple iPhone 5, Apple Ipad 4, Ipad Pro 12.9", Ipad Pro 11, Samsung Galaxy Tab S2, Samsung Galaxy Note 10+ 5G, HP Envy Laptop, Oculus Quest 1+2, and an MSI Bravo 15 Laptop. The only devices that have had issues with the Internet connection are the Note 10+ 5G and this Galaxy Tab S7+ 5G. Any ideas welcome.
The problem occurs with the mobile sim and Three's mobile bandwidths only run to just over 4 ghz. I've also looked through the settings and online for advice and there appears no way of altering the standard service relative to bandwidth.