Hey there, Welcome to the forums…
Sorry you are having hassles…
You havent provided your le_graphicsmanager.ini file so I am not sure what in-game settings you are using, but your GTX970 is unlikely to be able to maintain 60fps at 1080p on Medium settings - especially if you enable the special features (grass/antialiasing etc).
The game is generally unoptimised so performance related instability is often a problem - especially on low-mid range hardware. If your GPU maxes out for any length of time (i.e. not just spikes) then its very possbile that LE will become unstable.
There are many known situations in game where the game will max out the GPU unless appropriate limits are in place to prevent this - e.g. limiting FPS, chosing lower graphical settings etc. Scenarios on certain maps, lots of minions/mobs and screen wide effects and skill procs can definitely cause GPUs to max out and the Lagon fight with all the waves crashing back and forth is one such situations.
Your GPU being disabled is NOT something that LE could cause directly… It might have overheated or attempted to draw more power than your system was able to provide during playing LE when the game tried to max it out.
Please note, I am assuming that you are not having hardware issues - i.e. overheating, power delivery or just failing old hardware.
Considering your comment of disabling your GPU - I see in the diagnostic section of the Dxdiag file show lots of errors related to dwm.exe - this is the Desktop Windows Manager and is integral to using hardware accelleration in Windows and is directly involved with your GPU, DirectX etc… There are at least 6 crashes directly on dwm.exe… This could point to a corrupted Windows install, or various other problem areas - drivers, failing hardware etc. I would recommend that you Goolge this issue and see if any of the recommended solutions help. I would definitely recommend running things like Using System File Checker in Windows - Microsoft Support. I would recommend you check View Reliability History on windows to see if windows is reporting some other issues on your system. NOTE: I unfortunately have yet to see someone resolve a dwm.exe issue that didnt require a clean windows install or using a system restore point from a time before the error started happening.
On the subject of the diagnostics - I see that vgtray.exe (Vanguard by Riot games) is also crashing… I would recommend that you check this and update or uninstall it if you are not using it.
Note that Unity (the game engine that LE uses) based games also tend to have issues depending on other applications running at the same time so its best to make sure that you are not running anything else while testing LE… Vanguard would definitely be something NOT to run while testing LE.
Your Workaround: Lowering in-game settings is usually the first thing to try after updating gpu drivers & verifying the game files… If you are able to do the same content at lower settings, thats usually a pretty good indicator that you are suffering from performance related issues. The fact that you could revert them to higher settings again, could just mean that none of the subsequent scenarios are taxing your system as much (YET) and its likely you may have the same problem later when you try to do something … it may not present as a crash, you might just have a huge FPS spike or stuttering…
Changing Window mode could be directly related to the dwm.exe errors you are getting.
Your logs generally show various debug messages that could be related to your system struggling somewhat - there are graphical debug messages related to NavMesh and colliders and other NullReferenceException errors - these usually show up if the game is struggling. Its not the worst I have see related to performance errors, but these dont happen if the game is ok.
The player-prev.log is simply truncated - this would be when it crashed previously and the game was unable to trap any error itself.
There are a few controller debug messages in the log that seem to indicate its struggling between using the controller vs keyboard/mouse - controller support is not complete yet so this could be causing a secondary problem - its recommended that if you use either one or the other input method - i.e. dont mix and match while playing as this tends to cause issues. I doubt any of these were the reason for the crash though.
So… final thoughts…
I run the game on an i5-7500/1060/16GB/NVME system and over time I have found that running it at very low setitngs, all special features disabled with a 60 FPS framerate limit (very important) @ 1080p gives me the most stable and best performance for the current game beta state.
I would recommend that you dont go higher than Low settings - especiallly if you want to enable special features - Medium is ok on my 1060 but stability/performance suffers, and your GPU has more memory but I still would not recommend pushing the game right now. I would recommend you monitor your GPU usage while playing and aim for settings (fps limits, res, quality) that keep usage % between 60-70% while standing still in town. This usually leaves enough headroom for the GPU to spike without it flatlining and the game becomng unstable.
The devs have indicated that the next version of the game (0.9) will have improvements specifically related to performance issues so its likely that this will help out everyone across the board and will mean that those of us on older, low/midrange hardware might have a better experience… The patch is expected sometime after September… hoping for Oct/Nov personally.