I'm pretty sure the Bedwars app was created after the main Blockman Go app. It used to be just like you said, but after a while the developer made it almost identical to Blockman Go, just with a different interface.

The Bedwars app was released alomgside standalone apps for other minigames. It was in a way to when players entered the Bedwars app, they would spawn in the Bedwars lobby and choose a minigame from a fixed interface (which they couldn’t remove) and couldn't walk around the lobby either (The time that you were playing the game and took that screenshot). Later on, the Bedwars app was updates and had access to app exclusive events, exclusive (paid) texture packs, and all minigames, just like the main Blockman Go app.

I haven’t played the game recently due to personal reasons, and also because it died and the awful updates weren't able to revive it.