QWEEDDYZ: There is thread about Verok mod here in 'pinned topics'. Link should be there on some of the latest messages.

Reinstall\verify (better twice in a row since current Galaxy no more report result) game. To use with Verok - rename _ddraw.dll.
If you not want to use Verok - rename _ddraw.dll and make sure game itself work. Configure game ingame settings (do nto forget that 1280x1024 is 5:4 and NOT a maximum resolution for this game, use lower one isntead).
Go back to ddraw, rename it to normal, use dxcfg.exe and set everything to 'by application'. Check game. Then reconfigure few opion to what you like (do not change aspect ratio\pixel ratio options, let it keep).

Many report of that their Win10 not work with GOG DX wrapper (which one exactly for Win10). I dont know exact reason. Maybe ot latest stable update vuild for Win10. Or opposite - too much updaed (Win10 is Win10, broken entirely).

But first what can be suggested - reinstall GOG Galaxy (if you use it) and game to path:
X:\Games\GOG\
X:\Games\Heroes-4\
no C:, program files non-latin letters ' _ ' spaces and etc symbols (and nt even default path!).

it is probably doe to some security. And ofc dxcfg.ini file. DXCFG should have access to it, it cannot get it from 'non-Games' location.

Mendreklap: I am getting runtime errors when I want to launch the game. I reinstalled it. I do not see any ot the mentioned files in the game's folder to remove. This sucks, game worked fine, not it does not at all.