3W-4W is total system power (not just only the SoC) including the modem, screen etc. under sustainable conditions. For example the Samsung Galaxy S21 Ultra is drawing less than 3W system power - with screen brightness set to minimum.I know sometime they can peak 7w or 9w but average power consumption is way below that most of time 3w to 4W.
And in mobile there is soc not just cpu and Gpu, it need to power modem, bluetooth, wifi and other things, so that 5W envelope include things like that.
Andrei did publish some peak and sustained values for different phones last year here