The gear powerup cannot break the bricks in the save game room. The lootbox mushroom powerup does not give the powerup effect immediately like the normal powerups, but it spawns a powerup next to mario
1. The bricks blocking three pipes in the save game room isn't supposed to be broken
The obstacle that is blocking the pipes is a block, which cannot be broken by beetroots or gears. Bricks are items that can be broken by beetroots, gears, and simply hitting it while having a powerup. Bricks which contain coins or powerups cannot be broken.
In the above image, the brick is one on the left, and the block is one on the right.
Here, on this screen, you cannot equip the gear powerup because you cannot break these bricks before entering the level.
In the level you can break bricks with the gear like this picture, so it is a bit of inconsistency that is happening here.
1. Inconsistency... (can't hit coin bricks with gear) - see picture below 2. The star popping out of the lootbox mushroom doesn't give the star effect immediately, but instead spawns a star. 3. Gears don't hit Mario/Luigi switch blocks in the save game room 4. There's something wrong with the gear animation (pipe entering)