There have been various reports of memory related issues on Linux but nothing exactly pinpointed to a particular cause right now. A lot have been driver related (especially GPU & graphic subsystems) others have depended on the distro used (Ubuntu is currently the only officially supported Linux) and still others remain unsolved and transient.
To help the devs, please can you include more specifics as to your setup as reference. Things like uname, lscpu, lshw, hwinfo etc output. showing details of your Linux version, hardware, gpu, memory, drivers etc. With the Steam version, then you could try the system info option.
Please can you also include your game settings (usually in ~/.config/unity3d/Eleventh Hour Games/Last Epoch/ on Linux)
In the meanwhile… possible suggestions to address this issue (assuming you have not already addressed these):
is to double check the various gpu drivers etc to make sure you are using something recent… If you search the forums you will also seen info on Mesa versions, people trying with proton, vulkan etc… Perhaps there is something there that you could try/test.
Try the native linux version (this apparently works very well - I am still in the process of setting up a system to try the linux version personally) available from your account login page.
LE is in beta and has known performance issues - on Windows if people run into crashes like this, it is recommended that they reduce their in-game settings and test if the same issues happen - try 1080p, 60fps framerate limited (important), all in-game settings on very low or disabled… This is the most stable config irrespective of OS right now.
Obviously make sure your system meets the minimum requirements of the game. There are quite a few people assuming that their older hardware should be fine but personally I have found that anything slower than a 4-core 3ghz cpu with a 1060 level gpu doesnt really play LE that well and things tend to crash often unless everything is dialled back…