I've been using Linux mint on my Thinkpad t480 and everything works great except for suspend.
It takes somewhere around 10 seconds for it to show the login screen from opening the lid as opposed to windows where it was almost instant.
All my drivers are up to date and I downgraded the bios to 1.48 to see if that changed anything and nothing changed.
I've tried more recent kernels and nothing changed.
Note this applies to all Linux distros I've tried so far (Linux mint, kde neon)
For now i have it set up to just lock the screen on lid close but I wish I could properly suspend.