Your eSIM connects to FLOW, one of the two main carriers on the islands. FLOW runs solid 4G LTE across the busy tourist areas, so you get steady speeds where you actually spend your time.
Coverage is strongest on Providenciales, also called Provo. The Grace Bay resort strip, downtown Provo, and the main roads all have good signal. Grand Turk and Cockburn Town are covered too. On the smaller, quieter islands like Salt Cay the signal can drop in places, so plan for thinner coverage once you leave the main hubs.