Most "widescreen fixes" break down at 21:9. The HUD usually ends up in the center of the screen, with empty space on the sides. The HoMM5 HD Mod extends the tactical battlefield perfectly to the edges. For Samsung Odyssey G9 or LG UltraGear users, this is the only working solution.
This is the magic bullet. The mod dynamically repositions the UI elements. The town management screen, the spell book, and the combat log are anchored to the edges of your widescreen monitor. No more floating buttons in no-man's-land. heroes 5 widescreen fix best
There is to fix this properly without stretching the UI or causing game-breaking bugs: using the community-created H5_Widescreen Mod . Most "widescreen fixes" break down at 21:9