Sign up notification banner will show in this app (Samsung Members) if your device is eligible. It is only available for unlocked devices ie. SIM free, factory unlocked handsets purchased direct from Samsung or resellers and not from service providers.
If you look at the service provider software version. The code on the end will have something like EUX. If you go into settings. Down the bottom tap on About Phone Then tap on software information You will see service provider software version Normally last few letters say if its service provider supplied or unlocked manufacturer supplied
As Glenntech's put, the code at the end of the Service Provider version will identify if your handset is eligible. If you post the code or end of it on here then one of us will let you know either way.
The 'EVR' at the end is the CSC network code prefix for 'EE' so your handset originated on / was supplied by EE and is running their network Firmware version. It's therefore not an unlocked device and wouldn't be eligible for the Beta programme, sorry! It will be a matter of waiting for the official release of OneUI 5 and for the EE variant Firmware being pushed out OTA.
There's a lot of confusion about the term 'unlocked'. For Beta purposes then it's not relating to a device being unlocked to take any providers SIM card (a network unlock) but actually refers to the handset's Firmware version being generic / unbranded and the device being classed as 'factory unlocked SIM Free'.