I think its constitutional design is relatively apolitical
Relatively as long as we are talking about variations of parlamentary republic or other system without Great Leader. For example we can compare EU and USA of our timeline: one has functioning healthcare, public transport and labour laws, while other has system, that allows only for two right-wing parties to exist, both of which compete for sucking corporate dicks more. All this while election of Great Leader takes all attention from parlamentary and local elections.
And as you have said “if that’s who won in the national + EP elections”. Having oligarchy neigbour instead of leftist one makes domestic oligarchs more likely to win.
Russia looks funny