You shouldn't be having crashes when running without mods. Perhaps another issue with DEP. Add ff7.exe to Windows' DEP whitelist and give it another shot.
It ran a lot longer than usual with that, but did eventually crash. This time it was during a transition from one screen to another. No cutscene or anything special going on. Just changing rooms in the empty Shinra Mansion in the Nibelheim flashback.
I started just before running up the Shinra tower to fight the elevator boss and Rufus. The highway sequence and end fight all happened fine. In the APP.LOG file I then get this as soon as I exited Midgar to the world for the first time:
[00198331] -=-=[START OF WORLD MAP!!!]=-=-
[00198331] ERROR: texture cache is full and nothing could be evicted!
[00198331] ERROR: texture cache is full and nothing could be evicted!
[00198331] ERROR: texture cache is full and nothing could be evicted!
[00198331] ERROR: texture cache is full and nothing could be evicted!
[00198331] ERROR: texture cache is full and nothing could be evicted!
And that error continues a couple hundred times. I ran straight to Kalm and straight into the inn when I got there to do the flashback sequence. Made it all the way to close to the end after Sepheroth has been in the basement and you go back to see him. That's when it crashed. Just leaving the room where Cloud was laying on the bed. This is the end part of APP.LOG:
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242645] ERROR: texture cache is full and nothing could be evicted!
[00242646] ERROR: GL_OUT_OF_MEMORY
[00243071] ERROR: texture cache is full and nothing could be evicted!
[00243071] ERROR: texture cache is full and nothing could be evicted!
[00243071] ERROR: texture cache is full and nothing could be evicted!
[00243071] ERROR: texture cache is full and nothing could be evicted!
[00243071] TRACE: *** Exception 0xc0000005, address 0x1011449c ***
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\7H_GameDriver.dll
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\7H_GameDriver.dll
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\FF7.exe
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\FF7.exe
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\FF7.exe
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\FF7.exe
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\FF7.exe
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\FF7.exe
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\FF7.exe
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\FF7.exe
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\FF7.exe
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\FF7.exe
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\FF7.exe
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\FF7.exe
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in E:\SteamLibrary\steamapps\common\FINAL FANTASY VII\FF7.exe
[00243071] TRACE: at 3|%%3~|~|, address 0x8a0e990e910e510e
[00243071] TRACE: in C:\Windows\syswow64\kernel32.dll
[00243071] TRACE: at BaseThreadInitThunk, address 0x74ae343b
[00243071] TRACE: in C:\Windows\SysWOW64\ntdll.dll
[00243071] TRACE: at RtlInitializeExceptionChain, address 0x76f8979f
[00243071] TRACE: in C:\Windows\SysWOW64\ntdll.dll
[00243071] TRACE: at RtlInitializeExceptionChain, address 0x76f8979f
[00243071] ERROR: Unhandled Exception.
EDIT: I think it's important to mention that while these errors began as soon as I left Midgar and was in the open world for the first time, I experienced half a dozen crashes before ever leaving Midgar before I decided to come here and ask about it, so it has nothing specifically to do with the open world map. I don't have any other example of a non-battle related crash although it had happened several times within Midgar over the last couple of days.
As for the GL_OUT_OF_MEMORY, I've got 4GB of vram on my graphics card and I've got the maximum 2048 set in 7H.