machine.RTC().datetime have not the same params that utime.localtime()

machine.RTC().datetime((2021, 3, 21, 0, 16, 37, 0, 0)) # Y,m,d,0,H,s,i,0
utime.sleep_ms(100) # breathe a little
lcd.print(str(machine.RTC().datetime())+"\n") # print Y,m,d,w,H,s,i,timestamp
lcd.print(str(utime.localtime())) # print Y,m,d,H,s,i,w,z

It's not the same thing that official micropython documentation,
to set RTC, use particular tuple (year , month, day, week=0, hour, minute, second, timestamp=0)

regards
thomas