This Astrum video does a good job of explaining things. In short, China's experimental work on its space station is all targeted at practical steps to help it build a Moon base, and have manned missions to the outer solar system.
In particular, they focus on 5 key areas. 1. Orbital Construction Technology, 2. Space Robotics & Automation, 3. Energy and Propulsion Innovation, 4. Life Support & Sustainability, 5. Testing of Spacecraft Technology in Micro-Gravity.
They've already succeeded with key breakthroughs, including a system for producing oxygen that is far superior to the system on the ISS which needs a third of the ISS's energy to function.
America, partnered with Europe, is still pursuing its SLS/Orbital Gateway plans that look ever more doomed as time goes on. A wildcard are commercial space systems that could rapidly take-off. If not, by doggedly pursuing its plans, at some point China may pull into the lead in the space race.