I must say that in general sleep mode has been working pretty well for me over the past 10 years in Linux. I had issues on my destop, but tracked it down to a USB headset sometimes not correctly honoring sleep states. I also had a slight problem with one of my laptops when Bluetooth was paired, Bluetooth tended to be broken after coming back from sleep. though I have had more issues my current 2017 MacBook. often when I take it out of my bag after a weekend it will be on 1% battery. it stopped happening around Autumn last year so I think they fixed it.