Lots of good tips here. Here is what I do for business (outside US), and we do for travel.
1. Always use a high quality VPN on your phone (lap top, iPADs, tablets).
2. Use WiFi Calling whenever possible. We use Whats APP for texting/calling and we try to never use cell service when traveling outside the US. We turn off the cell connection. WiFi for Whats App calling texting on ship works just fine.
3. Caution: When traveling/cruising to China, never use your personal or company/business phone. Leave it at home. Get a "burner". If you take your personal (or company) phone, even if it is turned off - it will be cloned - that is, they will take all your information, personal and otherwise - immediately by the CCP. Taking your company phone to China is a fire-able offense at my company. 😁