UAE has Anti VOIP laws to protect revenue of their state owned their telcos (facetime / Signal / Viber / WhatsApp / Messager) are either blocked or have high data charges after a relax of some of the laws in 2020
They cannot block VOIP or impose high data charges on roaming SIMs as it is a Layer 2 protocol back to the home carrier so it's just high data charges for all roaming data.