If I suspend my laptop while it is connected to my Wacom tablet with bluetooth, it cannot wake up back.
The Wacom tablet driver is xf86-input-wacom if relevant.
Very difficult to debug, likely a firmware bug in your wireless adapter. I would try the following: See if you can safely stop and restart bluetooth while the tablet is connected:
# systemctl stop bluetooth.service
# systemctl start bluetooth.service
If that works without crashing, add these commands to the pre-suspend / post-wakeup scripts. Have a look at the powerManagement module options on how to do that.
This problem seems to have gone after an update a while ago.