About 1, since the snap uses classic confinement (that is, no confinement, no isolation) there’s probably something that it assumes about the host that doesn’t work for openSUSE. That’s a downside of classic confinement, that apps behave differently on different systems. You can report this issue to the maker of that specific snap and see if it can be resolved.
About 2, can you please tell me how such a warning looks like? I haven’t seen it before.
Did you download the .rpm manually or did you add the repository with zypper?