Ok, using Toshiba-3's awesome guide/mod here as a base, I think I've found a legit crash-free fix for GTA 2 on modern Windows (in my case 10). Before hand, the game would freeze every 3 mins or so, forcing me to log out and log back in of my computer. After applying this method, no crashes so far. No guarantees it will work for anyone else, but I don't see why not:
1. First you need to install GTA 2 11.44. I don't know if I can link to it, but it shouldn't be hard to find.
2. Install Nglide. You can grab it from here.
3. Launch Nglide Configurator and adjust the settings so they match these, then apply, save and exit the program:
Screen resolution: By desktop
Aspect ratio: Preserve original
Refresh rate: By app (Default)
Vertical sync': On (Default)
Gamma correction: 0.8
3Dfx logo splash: Off
4. Go the GTA2 install directory and launch the GTA2Manager executable.
5. Go the video tab, and change the Screen Mode drop-down option from "Direct3D" to "3DFXGlide". While you're here, make sure Frame Rate Limiter is ticked.
6. Don't bother selecting a resolution, just click the GTA2 button and the game should load.
I've played for a few hours and no crashes at all, yet before it would hard freeze every 3 mins or so. Again, just a tip to try. It might actually work for someone else, besides me.
Full credit to Toshiba-3 as well as all the other talented people in the community.
EDIT: Also massive thanks and credits to Sektor and Vike for patching the game for all these years. You're both top blokes. Cheers!