I’ve found okayish workaround for that - level to 2 normally by killing monsters (around 10 is enough) before reading the note
(that I also used when leveling chars with GDDefiler / to be able to select both classes)
Then you have both classes to choose.
Another option would be to use the free GD Defiler app, which allows you to edit your save file. You can reset your attribute points, devotion points, masteries and skills. You could also increase your character level, skill points, etc, but I have never used that because I only want to use what I have ‘earned’ in the game.
I have used it many times to reset my attribute points to fit equipment on my char, or to try different devotions easily. It even allows you to keep experience earned on devotion skills. I have used it many times without any issues.
Recently on my Warlock I deleted the Arcanist mastery and switched to Nightblade for better synergy. I also had a level 70 Inquisitor and reset the masteries so I could make him a Death Knight. He tanks like crazy but is boring to play, so I think I’ll reset him again and make him back to an Arcanist focused around AAR, like he was originally. Awesome to be able to do this easily, without losing game progress on the char.
You can open and edit the save file that is in your Steam cloud-save folder, so it does not require you to turn off Steam Cloud syncing.