ᐅ Silicone does not adhere in the shower area of the new build.

Hello, what do you think about this picture? It shows the transition between the floor and wall tile. The gap between the wall and floor was quite large because of the shower slope. Is the silicone sealant starting to come loose there? The joint doesn't look ideal either. Unfortunately, water always collects right at that spot because the tiles are set slightly too low. At the moment, there is no water leaking behind the silicone. We have been using the shower for two weeks.

Apparently, the joint was not sealed in one continuous process, and on the right side, it looks like the silicone is already peeling off at the top. This is not unusual in itself, but for a new build, it should not happen so quickly. Therefore, I would recommend contacting the builder and asking them to renew the entire joint. This will likely need to be done again in three to five years.

Yes, I also noticed that only from the picture, specifically the upper right area. Unfortunately, the builder is no longer responding. He made several mistakes. We also have standing water in the shower because he installed the drain slightly too high. About 200–300ml (7–10 fl oz) of water remains permanently on the tiles.
Unfortunately, I have no documented proof of the builder’s work.

Is it not possible to just apply something generously over it?
Alternatively, I was thinking of cutting out the joint in the affected area, removing it, and refilling it?
I would then basically start fresh on both sides of the old joint.

No proof?

Covering it up is definitely a bad idea. I would completely remove the joint and redo it from wall to wall. You can usually manage that yourself quite quickly, and if you use one of those silicone smoothing tools (joint tools) like they show on TV, it often looks really good.