This is the great Decline of Breakthrough.
Originally in BF1 we had the mode called Grand Operations, which was the father of Breakthrough. A longer mode with multiple maps and waves of reinforcements with even super vehicles called Behemoths as well as all the regular vehicles.
Then in BF5 with got a cut down version of the Operations called Breakthrough. It still had considerable vehicle presence but only one map at a time.
In the beginning of BF2042, there were helicopters and jets in Breakthrough. There were some balance issues but just when they were about to balance them, they also removed the combat aircraft from breakthrough, outside of the transport gunship.
So we are now on BF6 with more of the same like in BF2042 with pathetic ground vehicles and no aircraft to clean up the camping defenders from their rat holes
I have to call out DICE here for being Lazy with balancing Breakthrough.
Now it is a little more than a weapon XP grind mode