"How can I camouflage a ceiling beam that appears in the middle of the open-plan living room and kitchen? Under the beam, it is designed to place the kitchen counter with the sink. In the photos you can see, the water pipes on the floor. My basic concern is, that the counter will not be placed exactly under the beam but 50 cm in front of it"
Unfotunatelly, you don't have many options and a possible solution is to expand both the beam and the column, with a drywall construction. Then the edges of the counter top and the beam will overlap with each other. Over the counter, and inside the drywall you can install spot lights.
Picture above: On the left of the dashed line, they were sketched the existing column and beam. On the right of the dashed line, they were sketched the drywall constructions.
Picture above: It was sketched a suspended ceiling above the kitchen area to hide the beam.