Is the “Way of the Astral Self” Monk’s extra punch useless?

Martial arts for monks states that when you take the attack action you can make 1 unarmed strike as a bonus action. However Astral monks at third level says the same thing: “you can make 1 unarmed strike as a bonus action.”

I know at higher levels that increases but I’m asking about only level 3. Because you only get 1 bonus action does that make that extra attack feature from one or the other useless?

Also, flurry of blows makes 2 strikes as a bonus action so if you use that are both these abilities rendered pointless. Finally, at level 11 of astral monk you can make 2 strikes as a bonus action. Would this make flurry of blows a pointless ability? Have I understood this correctly or would all these abilities stack on top of each other?