@leicesterMan: I'm not sure why you're unable to establish a Bluetooth connection between your laptop and Galaxy S20 Ultra. If you tap the cog symbol to the right of the laptop in Settings > Connections > Bluetooth, select 'Unpair' then run through the connection process again, does the issue persist? If you have any other Bluetooth devices connected to the laptop or phone, please disconnect them temporarily to see if this helps.
To access your Bluetooth app settings, please head to Settings > Apps > Tap the 3 lines with the downward facing arrow, to the right of 'Your apps' > Show System Apps (toggle this on) > OK. Now, scroll down the list of apps, and Bluetooth will be visible. From here, tap Force Stop, followed by Storage > Clear cache, then restart your S20 Ultra. Let me know how you get on.