Wide silicone joint - can I replace it with joint mortar?

Stop! Once Sille, always Sille, nothing else sticks anymore. Besides, silicone doesn't have to be inferior, PU molds as well, MS polymer too, the problem always remains in the bathroom. Such a wide joint requires a silicone with low shrinkage. I would use Elch Pro Tile Silicone from Henkel. The Elch silicones are quite expensive, but the types used in shipbuilding are all top quality, durable, and shape-stable, even under UV exposure. Therefore, I trust Henkel to mix a premium product for bathroom use as well.