Shower trays not installed according to manufacturer specifications

A completely different question, if the screed was tightly laid against the tub, how can the, in my opinion, necessary sealing tape be applied from the drain to the surface? This tape should actually overlap the tub, so there should still be space from the screed to the drain. Similarly, the shower should be able to move freely from the screed or the tile to prevent any tearing and water running under the screed. Therefore, the question: how was it sealed? Maybe you have an approach because just fixing the visually disturbing edge would actually probably be disproportionate. Best regards

If you are not sure that everything will still fit together in the end, then I would leave it at that and keep the money. With sanitary installations, the interventions are usually quite large and difficult (and I think that's exactly why this trade likes to avoid responsibility when it has made mistakes, it was the same with us). It's not just a bit of drywall to change or something to plaster anew. It's definitely very annoying. But I would probably write it off. The shower tray seems to be working anyway.