Russia: Eh, no. That's just a temporary blip caused by a lot of the people born before 1945 not having made it that far, so the population was unnaturally skewed young. Few elderly to be dying off at the time because a large portion of those people died off 50-60 years prior.
They're set for sharp decline going forward, and changes in geopolitics look likely to dry up or outright reverse their modest immigrant flows from former USSR countries.
You're right. Japan's population pyramid is inverted [1]. Personally, I wouldn't call the rate ever more rapid— it's seems quite linear given that fertility rate has been pretty steadily around 1.3 since the 90s [2], but it is definitely still shrinking.
Russia's population pyramid does seem to suggest a big dip once the generation born in the 80s passes away, but it doesn't look like a reversed pyramid just yet. The generation born in 2021 doesn't seem considerably smaller than the one born 20 years ago [3].
They're set for sharp decline going forward, and changes in geopolitics look likely to dry up or outright reverse their modest immigrant flows from former USSR countries.
Japan: Is shrinking ever more rapidly, not less.