Samsung — S22 ultra Motherboard corrupted

The phone is just 15 months old and while talking on a call the phone randomly, out of no where blanked out. The black screen was persistent even when we were trying to switch it on. When we immediately showed the problem to samsung service center, they said it is a motherboard issue, it is corrupted. Out of no where they told us this and the phone costs so much and as soon as the phone crosses it’s warranty period, this happens. Now that we don’t have any warranty they denied to help us in any way other than change the motherboard which will cost us 40-50k. This is not at all done from Samsung’s pint. We have no where to go after investing so much in a phone. I want either a replacement or compensation.