- Laptop or desktop. I'd wager based on you post that it's a laptop -- ACPI on laptops is finnicky -- but it's still best to be clear.
- Basic hardware info. Some devices have issues waking (RL example: my controller needed manually waking until about kernel 5ish).
- Does the monitor turn on, yet show no image? This can be "man-patched" by switching to another tty and then back to the video one (I do this on my laptop since Deb 11 broke something that I'm too lazy to fix ATM). If you start X manually, the tty on which you started (usually 1). If your Display Manager, most likely with Ubuntu, starts for you, then it'll be on 7.
- Be more specific about "not start" (see how the above route is very specific to my issue, yet there could be a number of interpretations of "not start", a' la disconnect from and shutdown X server without it starting back up, or a hardware freeze when a component comes out of low power).
What system do you have so what hardware, as in the graphics card may also play a role in resuming. So when it is suspended and you press one key it doesn't respond either? I did come across this, you seemed to have tried the last resort but did you also just press one key? I've seen configurations where "resume" is mentioned in the grub configuration and that might have some effect as well. Also how much swap memory does your installation have, if I remember correctly if you want to use the suspend/resume option under Linux your swap should have the same size as the actual amount of ram in your system.