You use your iPad Pro as your main device for work and travel, but since it doesn't have cellular, you rely on your iPhone as a hotspot, using two SIMs (T-Mobile and a Verizon MVNO) for better coverage. To keep your iPhone powered, you carry an extra battery. While having an iPad with cellular might have been convenient, this setup works for you because it provides flexibility and reliable access, especially when traveling.
You could also explore options like
Globe SIM registration for additional flexibility when traveling, especially if you're considering international travel. Having a registered Globe SIM card could allow you to easily switch to a local network abroad for better data coverage without depending on Wi-Fi or draining your phone battery as a hotspot. Globe offers roaming services, and registering your SIM ensures smoother access to these features. This might complement your current setup, giving you more connectivity options while traveling.