If you don't use the client, do cloud saves even implement with the offline installers?
Is there a risk for cloud saves causing problems with the games using them if the servers are down etc and acting like almost DRM?

No GOG Galaxy = no cloud saves. I've never heard of a developer wasting time and money to implement their own cloud save system, when this feature is provided by the platform.

Any game with offline installers can be played offline, with whatever limitations are listed on the store page, if any. Sometimes, there are sneakier, more subtle things that you miss out on by playing offline. Check the DRM on GOG: list of single-player games with DRM thread for those.

No, as above, cloud saves are galaxy only (even though galaxy parts are n offline installers as well).
However, there is a far better system available to you. It’s fancy and new and you might not have heard about it. It’s called copy and paste. With this method you go an backup, copy around, send wherever, saves as much as you want, completely under your control. You could save various progressions, mod states etc. all controlled by you. Amazing power!

So having an offline installer which has been patched to support cloud saves means what? That in reality there is no cloud saving in the offline installer? Then why patch it as such and claim it is a new version? I will keep it polite. Don't be like that. I am not in favor of cloud saves or cloud gaming in any way. My worry is that the offline installers which are clearly patched as having cloud saves enabled files, will cause issues in the future when said servers or connection is not available even though I have no desire to use them in the first place.

I don't know what you mean by this. If you could link to whatever post or page you read about it, that would help.

To hazard a guess, it sounds like you expect the offline installers to provide a completely different version, which isn't how it works. Just as you can often find steam_api*.dll in the installation folders of games from GOG, you can also find GOG Galaxy components like Galaxy*.dll in games installed via offline installers. The support for GOG Galaxy features is there, but those features don't work without GOG Galaxy.

To put your mind at ease, I suggest that you find a recent game in your library that supports cloud saves. Install it via the offline installer, then play it with no Internet connection.

Sorry, didn’t read it correctly. Then the answer currently is no. It currently is a system for copying saves from a directory to the galaxy folder on you system, then galaxy would copy those. If you don’t have galaxy installed it doesn’t do anything.
This of course doesn’t mean it will change in the future, they already updated all the installers without changelogs to include galaxy functions, breaking some games, and removing content in the process. More likely is that galaxy.dll will break and all your games will stop working. But hey galaxy is what most want, so we all have to live with it. Someone has to respond the increasing number of “galaxy is wonderful, gaming can only happen with a client” idiots which have destroyed any difference on this site and mean people have to ask these types of questions in the first place.

Thank you all for your input.