The wither's dash, which can normally destroy every breakable block in the game, including netherite, is not able to destroy obsidian.

For further context of the video, I used command blocks to massively increase my strength and resistance for the sake of the video, and I also used the command blocks to kill wither skulls to prevent them from affecting the experiment.

The resource pack used merely changes textures for aesthetic reasons. It does not affect gameplay.