No, you do not need to install one eSIM profile per country, nor do you need to install multiple eSIM profiles at the same time. You only need to install one eSIM profile on your device for all your travels.
Indeed, a single Ubigi eSIM profile installed on your device will allow you to connect in all countries.
After choosing the data plan corresponding to the country you’re traveling to and completing your purchase, install your Ubigi eSIM and enjoy connectivity!