In Senegal this eSIM runs on the Yas network, known until recently as Free Senegal and before that as Tigo. It is one of the country's main mobile operators and it carries plenty of 4G across the cities. Your phone picks the network on its own once the eSIM is turned on, so you do not need to choose anything by hand.
Yas is strongest in and around Dakar. The capital, the suburbs of Pikine and Rufisque, and the busy Plateau district all get a steady 4G signal. Thiès, the second city inland, is also well covered. If your trip stays in these areas, you will rarely lose service.