Especially in the bathroom, which is only 3 meters wide :D
Is that the case here? I have no idea about such things, I actually like very plain tiles. :D But if it's only about "no joints," which seems to be very trendy right now, then you could also do those exposed concrete things or something similar? I've seen that quite often in ads, for bathroom walls things that look like "plastering," which then result in a very smooth, joint-free surface.
Of course it looks great, otherwise I wouldn't have chosen it ;) However, for me they are on the shower wall, not on the floor. I'll look for a picture of it later.
My parents-in-law build bathrooms and have something like that in their exhibition. It already looks good, but they talk about similar costs for the installation, and that in a rather structurally weak region.
With us, the large one (160cm x 320cm) cost 1000€ and the small one (120cm x 240cm) 700€. Material, meaning tiles and adhesive including laying and processing. This always cost the same for us because it doesn’t matter whether I have to cut off 5mm or 20cm.