I base this on absolutely 0 military experience BUT

Could be a distraction vessel to draw fire

Could be to give Russia a chance to use countermeasures and evaluate their effectiveness + come up with next Gen drone to mitigate current countermeasures

Could be that it is impossible to get a good video from a drone bouncing around in the water and they wanted to make contact with areas that ensure sinking

Could be a test to see how much punishment the drones can take while maintaining combat effectiveness

Could be that it's pure chaos and neither side has a great strategy aside from do/do no explode if possible

Either way, this footage is wild! Give em hell Ukraine!!