There are plenty of solutions actually.
1. Miracast (cost: Miracast receiver $50-100)
+ Wireless!
- Only 20-30fps for 1080p (if you need to watch videos, that's fine. if you want it for productivity, dont)
- Not as stable as wired connection
2. DisplayPort splitter (cost:$50-100)
+ No degradation in performance and quality
3. USB display adapter (cost:$100-150)
+ Also acts as a USB hub
- Taxes the CPU
4. Monitor with DisplayPort daisy-chain (cost: $200+)
+ No degradation in performance and quality
5. Ultrawide monitor, like 2 monitors in one (cost: $200+)
+ Only one cable to plug
+ No bezel gaps compared to multiple non-ultrawide monitors
+ One less monitor to manage, one taskbar, one canvas, etc
- Still, its only one monitor
6. Get the docking station (cost: $150-200)
+ Fully compatible with the SP3, it even charges the SP3
- Only compatible with the SP3
I would go with either option 1 or 2 depending on the usage.