Hi everyone.

After the last update, it seems that the game does not recognize the settings of the GL wrapper, so the game appears less "smooth".
How can I solve the problem? Thank you for your support.

Just updated the game..
Can't move the crosser(mouse) without problems as you mentioned as well.

It seems the game now autoloads DDraw Compat with xdd.dll first??

So to make other wrappers work, rename your wrapper's ddraw.dll file to xdd.dll (rename the original first). I've tested this method under Linux Wine with cnc-ddraw and GL Wrapper and it works.

It would be a better idea to just leave the original HoMM 3 executable as is, since it doesn't rely on DDraw Compat (which is neat under Windows, but doesn't work under Wine as far as I know), and just using the base DDraw Compat's .dll files should be enough anyway.

At Wine no wrappers needed at all. I wish Wine for Windows (which is bruh moment, but needed to play old games flawlessly). Although there is WineD3D-for-Win as partial port.

To get smooth 4:3 you no need HeroesGL. But indeed additional tweaks required since WinVista and easiest way is use 3rd party wrappers. So HeroesGL is minimalistic authentic (clear game) way version of HD+ mod (which become based on HeroesGL), while DDrawCompat by Narzoul is more authentic version of HeroesGL. Game remain completely untouched unaltered. I would say smoother than HeroesGL.
Unless it is about non-4:3 aspects, for widescreen DDrawCompat allow to stretch the screen but HeroesGL do it better. Not ideally (not possible to). And general solutions cannot do what game specific mods can.
Also HeroesGL allow to speed up the game. DdrawCompat do speed a little as side... As main effect of fixing broken Win8/10+ Legacy DirectX.

For Windows 7 a bit easier to solve DirectX Ddraw issues. And that would be more smotthed 4:3 way. Heroes 3 itself, and Heroes3 itself cannot be non-smooth.

I don't understand the technical... The game is still unplayable

Same issues here. In fact it's affecting my whole pc. The graphics on other games looks washed out and less sharp. I uninstalled HOMM but it still persists. Splash screens are no longer full screen on HOMM and other games.

You can select scalling mode in wrapper settings. Default is bilinear(0). Dont know what it means but an image looks pixelated, really not smooth. I changed "Displayfilter" parameter to biqubic(0) or to bilinear with increased blur (~20-30 looks ok). It is possible to try different settings by pressing Shift+F11 but they will not be saved - you have to edit DDrawCompat.ini file.

For example put this string there: DisplayFilter=bicubic(0).

What is default scalling mode for Nvidia driver or for monitors? And how to make HMM3 look as before? Or maybe look better.

You can save the settings from the overlay too by clicking on the Export button. It creates a separate .ini file, but it will also be read and used on startup. You can find more info on the wiki:
https://github.com/narzoul/DDrawCompat/wiki/Configuration

If you prefer to use your GPU's or monitor's scaler, you can use the "DisplayResolution=app" setting.

NVIDIA's scaler is proprietary, so it cannot be replicated as far as I know:
https://forums.developer.nvidia.com/t/nvidia-scaling-algorithms/254672
They do have some image scaling SDK nowadays, but I'm not sure if it can achieve the same result.

I might add support for libretro's common-shaders (https://github.com/libretro/common-shaders) in the future. I don't really plan to add more built-in filters, mostly because I don't want to add any additional license terms to the currently very permissive licensing.

Smoth settings for video driver and display is set to Keep Aspect ratio plus Integer scaling and force by driver checkboxes (there are such checkboxes for Nvidia drivers specifically). Stretch to full screen is exact non-smooth option which do worse of all possible ways.
Display or TV used as display most likely have own scaling aspect or zoom options. Some monitors market as gaming have exact scaling method to choose identical to video driver. TVs most likely have predefined aspects to choose. Display set to stretch (or 16:9) do that without noticable blured and disproportion screen image. Whatever display settings video driver set to stretch always noticable disproportioned and blured.

3rd party wrappers is compromise variant to set them to stretch/ratio off. No miracles possible, but much less noticable image quality degrees.

If you did play clear Heroes 3 now it should look better with DdrawCompat. It can look worse if you did play with HD+ mod or HeroesGL. And how much better/worse depend on video driver settings too.

GOG did pre-install some compatibilities made by Ms ACT (AppCompatTool), they instaled to the system and stored in many places in Windows system folder and Registry,l - but they never affect whole system, only specific exe.

I still don't understand any of the technical terms you are talking about.
I still can not play the game.

Also I don't have setting anywhere so changing resolution or what not is just not an option.

You can change display settings from Windows -> Control Panel -> Display, or just by right clicking on your desk top. The latter may also bring up the Option for your video card.

Last time i check it video drivers require set lower resolution/4:3 set on Desktop first. Then additional menu about ratio settings become available. After set to keep (black borders should appear on Desktop) switch resolution back to maximum/whatever you want on Desktop.
I forgot such detail.

For Nvidia NV Experiance are NOT the driver or driver control panel and better avoid of using it entirely. If you still want it for some functions - make sure it was not mess with game and driver settings, not intefer game window by own overlay without reason (if you dont want to use Shadow play overlay set it to off). Set all functions to disabled.

You mean to bring my whole pc resolution? I have other programs running.

Still no update and game is unplayable.