Also not an issue if you're in the rich part of the world, or just one that has a lot of water. Fortunately I don't think water is gonna be what makes Russia invade, don't know what their supply looks like but I can't imagine it's not enough.
Russia has the largest freshwater lake by volume, Lake Baikal, so they aren't likely to invade anyone because of their drinking water needs. Especially because Ukraine has been instrumental in reducing their need of fresh water.
It's a big lake but a bigger country. I don't think Russia will be the first to have big water issues. Rather, I would look to Mexico City, Panama, Arizona, Nevada, California.
There definitely will be other areas with far greater issues.
Russia has a current population of around 143.8m people. One quarter of the Earth's freshwater is in Russia. Lake Baikal has a total volume of 6 quadrillion, which is 20% of Earth's freshwater.
The average Russian household uses 64 gallons of water per day. So Russia, with only Lake Baikal, has enough access to freshwater for over 10,000 years if no water is added to the lake and the population doesn't change.