The Russian "Collector's Edition" has an issue:
In version 1.60 of Heroes, at a resolution of 1920x1080, the image is clearly stretched vertically. Or, in other words, stretched horizontally. If you switch to any 5:4 resolution, everything is normal; if you use 16:9, it's stretched.
Is there no windowed mode in 1.6? And why isn't 3.1 suitable for you? It's time to stop using 1.6 and 2.1 because even campaigns from them can be played through 3.1.