Power dissipation of LT3083 for 2.5V
Based on worst case power calculated of 2.6W, the copper area used (~95sqmm top and ~45sqmm bottom) is not enough and might lead to very high Junction temperature. Also vias should be Capped and filled (IPC 4761 Type VII) since is a via on pad but this might help to increase thermal dissipation from top to bottom.