Alkaid Wang
In the impression of foreigners, China is just an ancient and mysterious country. But in fact, China's technological and economic progress interprets it as a country with contemporary charm, so I think these modern buildings can be used as a symbol of China
1.Oriental Pearl TV Tower（东方明珠）
A 468-meter-high radio and television tower, located on the east bank of the Huangpu River.
https://en.wikipedia.org/wiki/Oriental_Pearl_Tower
2.Beijing National Stadium (Bird's Nest)（国家体育场/鸟巢）
A large sports venues. Built for the 2008 Beijing Summer Olympics, it still hosts the opening and closing ceremonies and some competitions in the 2022 Beijing-Zhangjiakou Winter Olympics.
https://en.wikipedia.org/wiki/Beijing_National_Stadium
3.CCTV Headquarters(Big Pants)（中央电视台总部/大裤衩）
A 44-story modern building with a strong sense of geometry, the new headquarters of CCTV.
https://en.wikipedia.org/wiki/CCTV_Headquarters
4.Zhengzhou East Railway Station（郑州东站）
A giant high-speed rail station in central China. It has 16 platforms and is the most important hub in China's high-speed rail network.
https://en.wikipedia.org/wiki/Zhengzhou_East_railway_station
5.Five-hundred-meter Aperture Spherical Telescope(FAST/Sky Eye)（天眼）
The world's largest radio telescope, with a diameter of 500m, is used to observe the sound waves produced by the Big Bang and the rays in the space.
https://en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Spherical_Telescope
6.Danyang-Kunshan Grand Bridge（丹昆特大桥）
The longest bridge in the world, with a length of 164.8 kilometers, is a part of the Beijing-Shanghai high-speed railway, passing through southern Jiangsu, which is rich in water resources in China.
https://en.wikipedia.org/wiki/Danyang%E2%80%93Kunshan_Grand_Bridge
These are the only things I can think of right now, but there are many, many buildings that can represent modern China. I hope that some modern Chinese architecture can be added to the new postage stamps in the future.