Suspend does not work anymore on Fedora 31 kde

After a reboot of my Lenovo Thinkpad T540p with both Windows 10 and Fedora 31 KDE installed (dual boot), after a suspend is issued the screen goes black and the fan velocity increases, then nothing happens. The computer is unresponsive and the only thing I can do is to power it off. I tried to edit /etc/systemd/sleep.conf in this way:

#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.
#
# Entries in this file show the compile time defaults.
# You can change settings by editing this file.
# Defaults can be restored by simply deleting this file.
#
# See systemd-sleep.conf(5) for details

[Sleep]
#AllowSuspend=yes
#AllowHibernation=yes
#AllowSuspendThenHibernate=yes
#AllowHybridSleep=yes
SuspendMode=suspend
#SuspendState=mem standby freeze
#HibernateMode=platform shutdown
#HibernateState=disk
#HybridSleepMode=suspend platform shutdown
#HybridSleepState=disk
#HibernateDelaySec=180min

Now the suspend works as intended only some times, and I don’t know what causes it to fail.
Suspending by Windows goes well.
Output of uname -a:

Linux T540p 5.8.13-100.fc31.x86_64 #1 SMP Thu Oct 1 21:46:25 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

Thank you to everyone who will try to help me out.

I have also filed a bug to the Nvidia developer forum with log messages and other details, because I suspect that using the propietary driver of Nvidia causes the problem.
link to the bug

I’ve found the culprit. The suspension problem was caused by presence of AKE 2 port USB 3.0 expressCard 34mm NEC UPD720202 Chip. Laptop can’t properly suspend when it boots with this card plugged in. I suspect it is a problem with this card in particular, because I did a test with a Sony Vaio memory card adapter VGP-MCA20 express card 34mm, and suspend happened without problem when prompted. Maybe the NEC chip is not compatible with Fedora 32? (I know nothing about how express cards are handled in Fedora so I’m sorry if I’m sounding stupid)

Is there some chance I could get the USB 3.0 card work on my laptop without giving up to suspension?