It is normal to feel nostalgia about good old times when we were younger, yet you assume the motivation is a “colonial empire” (SU was very different from British or Spanish empire in that sense, I’m not sure “colonial” even applies to it economically — this is a political narrative of former republics, which were colonies of Russian empire).
It is a stretch. Majority of Russian population couldn’t care less about the statehood of the former Soviet republics and nostalgia for SU is not the base of the current regime (ideology of which is a conservative nationalism very similar to MAGA). This nostalgia existed in 1990s too and has same nature and features as in Germany.