But even if mandatory RFID IDs were a critical tool of authoritarian governments, what would prevent the dictator from issuing mandatory IDs after taking power?
What prevents a dictator from issuing mandatory IDs? The resistance of the people. Yes, the government has police, and an army, and fighter jets, etc. But in the past few decades we have seen that insurgencies and popular resistance can succeed anyway -- the US got kicked out of Afghanistan and had a lot of trouble in Iraq, Ukraine is outfighting Russia despite massive disadvantages numerically and technologically, and even in China the government softened the zero-Covid program after mass protests. The people have more power than we think and can resist such things, if they want to.
Unlike facial recognition cameras, which there's at least some political will to ban (https://www.politico.eu/article/europe-edges-closer-to-a-ban...).
You are somewhat misinformed about the Ukrainian war. Ukraine has 3-4 times less population than Russia, but it started full mobilization early in the war. Meanwhile Russia started partial mobilization just recently. So it was common for the Ukranian army to have a numerical advantage on the ground. Most of the recent Russian retreats can be attributed to the lack of personnel to properly mount defensive positions.
As for technological advantage... It depends. Ukraine effectively has the whole NATO and a number of additional countries as its rear and supply base, while Russia depends only on itself and a bit on Iran. In terms of communication systems, intelligence, and likely anti-tank and anti-ship systems, the Ukrainian army is miles ahead of Russia. Russia has advantage in air, artillery, anti-air, and ground-to-ground rocket systems.