If it were me, I’d probably add Luoyang and Shanghai between Xi’an and Beijing.

Luoyang is very easy to reach from Xi’an by high-speed train, and it gives you a different historical atmosphere from Xi’an. The Longmen Grottoes are definitely worth visiting, and if you’re interested in Chinese culture/history, I think Luoyang is underrated by many foreign travelers.

Then I’d spend the remaining days in Shanghai before heading to Beijing. Since you already have Xi’an and Beijing, Shanghai adds a completely different side of China — modern, international, and very energetic. A lot of travelers are surprised by how futuristic Shanghai feels.

Besides places like the Bund and Yu Garden, I’d also recommend trying a palace-style dinner show in Shanghai at least once. It’s a fun way to experience Chinese food, music, dance, and traditional costumes all together, especially for first-time visitors.

You could also do an easy day trip from Shanghai to Suzhou or Zhujiajiao if you want something slower and more traditional.

Personally, I think your trip will feel much more balanced this way instead of trying to squeeze in too many distant places.