Please, Fix your designer and bug report system.

@Looney if you buy a car and it doesn't fly it's not the car's fault.
Attachment points is how mafia works, you have to learn how they work, I can try to help you a bit if you want

@pedro16797 That's not it. The designer is pure cancer whenever I remove a part and try to put it back on.
That part was literally just on my rocket, and then it suddenly cant be put back on when I add more fuel tanks.

The problem is you're using bad the tank for the battery' you have the tank rotated 90º, so it's not the game's fault, it's yours.

You can fix this selecting the battery and the rotation tool, select "Self" and rotate it 90º and then change the horizontal and the vertical values in the part shape tool, you have to leave the attachment point in the bottom if you want to connect the part from the bottom.

The camera zoom is quadratic or logarithmic not linear, which aids construction of crafts of varying sizes.

You can also turn off “auto-rotate” if you want to connect a part in a certain orientation. You can also use the offset and rotate tool to move your battery anywhere and in any orientation.

You also just described the bug in this forum post. What prevents you from writing the same description in the bug tracker?