Thank you.

Do you know what's the last version without Red? I have 4.04 saved.
Also, is it problematic and should I avoid it? (telemetry, ram requirement, online checks, etc..)

For This War of Mine, I see that my files have "_testowy_build_2" in the name, so I guess that's why they changed it XD

I think 4.04a is the last version (not sure if 4.04 and 4.04a are the same), while 4.04a_Launcher adds the launcher. I have no experience with the launcher but afaik it is used to handle online rewards like Cyberpunk 2077, the subforum probably has more info about it.

You can safely update. After you update to a version with the launcher the launcher will launch by default (surprise ;) ).
But if you want to skip it you can still run the game without it by running it directly from the game's executable. For me that is the following file: \The Witcher 3 Wild Hunt GOTY\bin\x64_dx12\witcher3.exe