A Bavarian is not an Eastern Frisian, a Scotsman is not an Englishman and there is no such thing as one Russian-German because they have never been a homogeneous group.
The numerically largest group among the Russian-Germans consisted of farmers living in regions with Russian-German influence. But even those farmers differed from each other. They had varying dialects, denominations and were spread all over the enormous Russian empire which had an impact on individual cultural development. Traditions and individual cultures were developed in their families and even more in social institutions like schools, churches, through newspapers and magazines, and last but not least via village communities due to their autonomous structures.
Germans that lived in cities, however, were quickly integrated and had adopted the Russian culture. Very soon after their immigration they were already called Russian Germans, whereby the word Russian referred to the meaning of being Russified.
Russian-Germans thought of themselves as a mobile identity and culture. Whenever they moved to a different place, which happened rather often, they carried along their culture. Nevertheless, they did not live separated unto themselves. External influences impacted their culture and their self-understanding. Such influences were for example neighbors, economic, and political factors.
Another example was language: until 1941 more than 75 % of Russian-Germans was able to speak German. Between 1959 and 1989 the number of German-speakers went down to 48.7 %. Speaking German was no longer part of the German self-understanding and therefore vanished as a part of Russian-German identity.