Hi GMarco_Utech12,
I did test on BMP388 reference board with the following register writing values. BMP388 current consumption was less than 2uA.
reg : 0x1B data:0x03
reg:0x1C data:0x00
reg:0x1D data:0x04
After writing register values, I also double check register value with register reading.

Could you read out register values to check them on your board?