Installed the game hit play, selected resolution, hit ok and game just won't launch and play button in gog galaxy becomes available again.

Already tried the fixes mentioned on PCGamingWiki, setting the exe to launch as admin, compatibility to win 7 etc. not nothing works.
Solved. Wrong installation order of the fixes.

Fixes? If you install something else rename bundled _ddraw.dll (and _dinput.dll probable too). you can keep DXCFG exe and ini/dixi.ini files. This is already bundled wrapper fixer by GOG

If I is about clear GOG/GOG Galaxy - it is strick security issue. I don't think it is DEP service (useless/always broken since WinXP) not even that one. More to just AV.

Game clients also must be excluded from AV and enabled adminrun.

But first mud he reinstalled to
D/Games/GOG/Galaxy and games strickly to
X/Games/
no system drive, no drive root, no non-latin symbols or anything, no spaces but "-" (minus) instead.

Make ADMINRUN for first launch of Galaxy, any launched with configuration, next time relaunch Galaxy in admin when you about to install/update/verify any game.
You no need to add ADMINRUN to game exe if you use Galaxy. Just restart Galaxy in admin.

Verify game installation after downloading!

Next launch the game, while Galaxy still in admin mode. Up to main menu. Then relaunch Galaxy without admin. Now game should be OK without adminrun. Before game launchband configure ingame pre-launch configurator there is DXCFG.exe in game folder. Run it always in Admin and configure there too.

Usually that's enough (X/games/ path on non-system drive for all games and gaming client) for standard Microsoft AV.

Still better ENTIRELY disable DEP service by some CMD command. Google it "dep nx bcedit" for correct command argument. There is a chance it don't like GOGs wrappers two dll and DXCFG exe.

Well. System related folder (for Galaxy client!) maybe not the case now.
OP did say it is about wrong order fixes. And which one is right and solve the issue, with which one fixes he install?
I don't think GOG compatible with any as is after install. First it is adminrun install + verify - still in adminrun configure DXCFG - start the game up to main menu and configure there too.

And relaunch Galaxy+game without admin again. Check settings are right.

And only then install additional fixes. But that one _ddraw.dll - in game folder should be renamed for sure. To disable DXCFG. And experiment with dinput. Depend on which fixes to install. In any way how Wrace fixer-mod work (and require bink-patch by Wrace?) this is first and probably second step.
Did it have any else/further order? SR1 Hook require bink-patch and require it to be pre-installed (not after SR1Hook)? Hmm, did PCGW article clearly state that...

By the way #1. Reminder that previous GOG build work well too, and they work cause previous builds always been based on earliest fanmade fixes from Nosgothica site (same Wrace).

By the way #2. If some 3rd party fixer-mod or GOGs DXCFG have resolution option it should match Soul Reaver ingame/Launcher resolution as one way, or set ingame option to lowest as other way. Make sure its not set higher for ingame.

........
dxcfg same as any 3rd party wrappers (dege voodoo or game specific fan maded) settings applied to what you set in the game. Ingame settings still in use for all of them.
Eg Warcraft 3 (1.27b before Warcraft 3 Classic release 1.28) have wide-screen resolutions and there is fanmade resolution switcher tool to apply a bit better proportions. To do that ingame resolution should be set one of the lowest 4:3 resolution and 3rd party wrapper/-tool should be used to apply correct widescreen resolution. Wrong set lead to unavailable areas at edges of the screen.
Same effect with Disciples 2 on GOG and their pre-bundled DXCFG without 3rd party downloads. And still same with 3rd party downloads. There is guy named Verok(Verokster) who made GL wrapper mods for few games. To make them work always in windowed or fullscreen-windowed mode. There is DisciplesGL required set ingame resolution to 800x600 to properly scale it.
He have KainGL for Blood Omen as well. Although Blood Omen have no resolution option still keep in mind how his wrappers work (windowed) and that mean they use Desktop resolution - and refreshrate.

For Soul Reaver it is SR1 Hook by Wrace linked on game article on PCGamingWiki website. Googleit or go to Game entry on GOG/Galaxy - MORE - Support - Additional info on PCGW.