Agree that having the side LEDs indicate standby would be nice, especially since Modern Standby doesn’t always go to sleep when you tell it to.
I found that the power LED is slightly visible when the laptop is closed if you look at it from behind like so:
However the issue with this is that I’ve found whether the LED stays on to be inconsistent while the lid is closed.
One workaround I use is disabling wake from standby upon opening the lid so I can quickly open it to check.