The Great Tribulation is broken up into two periods - 3.5 years of peace and 3.5 years of political turmoil that ends with the battle of Armageddon. The signing of a peace pact with Israel and the world is when this 7 year time period starts. This pact is headed up by the Anti-Christ.
The 3.5 years of political turmoil and true persecution occurs when the pact is broken by the A/C.
The Marrk is absolutely voluntary, and is unforgivable. Scripture is exceedingly clear on this point. It is easy to see how many would take it for convenience based on what’s currently going on. Scripture doesn’t say that those who don’t take the mark will be beheaded. It says that they will not be able to buy or sell. The killing does come about, but it doesn’t specifically mention beheading for everyone that doesn’t take the mark.
China/Russia coming into play specifically as Gog/Magog is after the 1,000 year reign of Christ, which is after the Battle of Armageddon. IOW, we got a ways to go.