Trusting the Thinkpad spec sheet numbers, an AMD T14s lasts >15hrs in one of the benchmarks on a 57Wh battery. That's less than 4W. Perhaps on Linux and with some tuning, it seems plausible to get to 3W?
Trusting battery estimates? I believe apple claims my m3 mac is capable of 15 hours or so. If I’m lucky I will get like 7 hours with a basic documentation webpage open and the terminal connected to ssh.
The estimates appear to match what notebookcheck[0] reports on their measurements - 4.4W idle average. With some tuning[1] and turning off unused peripherals, I expect to go below 4W idle.