To make this shorter: it is NOT necessary.
If your X2A is running on SFOS Demo version, then you are ready with all this difficult things (Flashing). You don’t have to do all this again!!!
Take your credentials for your Jolla account, go to Jolla shop using your computer, buy a licence for your phone. Print the bill and write the login creds for the Jolla account on the paper.
After this, take your phone, go to Settings - accounts and delete the existing Jolla account. Then reboot the device. Then again go to Settings - accounts and create a new Jolla account with the existing credentials you wrote on the paper.
After this, login into the Jolla Store with the phone should be possible again, and there should be Android support available under ‘best apps’, near the top of the list.
Now the IMEI number of the phone is tied to the licence, and you’ve got access to the licenced stuff even after later updating or reflashing the device, that you maybe want to do in future.