

journalctl is usually the way yes, you can also check dmesg if it’s part of your distro.
Errors are usually highlighted in red, that’s something to scan for. You can use journalctl -ef
to keep the log updating on your screen, if the issue is intermittent, it might take a bit before it shows up. If the issue is logged on boot, it should be in journalctl -b
Does htop/free show the correct amount of memory?
Also try applying load on the system, maybe it’s a thermal or power delivery issue.
Do you have a overclock enabled in your bios? Try disabling that and XMP if enabled.
You could try clearing the cache in Heroic? It’s under settings -> Advanced