The reason it was in Beta was for the testing of the new KnockBack, the Beta Skywars has now been removed due to the KnockBack release on the entire Bedrock Network.
If you still want to play SkyWars Solo (The same as it was in Beta), you can go to the SkyWars Lobby and go to solo's, as that is the same as the Beta Game. (You just can't go into games with a party).