Hello,
Voltage/temperature measurement only accessible once the FPGA passed configuration and successfully enter user mode.
It depends on your design and when you compare the temperature- if you are running the design with high speed IOs, the region which transceivers are located will show higher temperature/current consumption. If the FPGA sitting idle without running anything, you will see the VCC(including SDM) is higher than other region. you may want to get reference from PTC for your design. link : https://docs.altera.com/r/docs/814008/24.3/thermal-design-user-guide-agilextm-5-fpgas-and-socs/power-and-thermal-calculator-ptc
regards,
Farabi