Yes, WhatsApp, FaceTime, and other video/voice calling apps work perfectly fine in Slovenia without any restrictions.
Slovenia has no government-imposed blocks or throttling on Voice over IP (VoIP) services. This means that as long as you have a stable internet connection, whether through Wi-Fi or mobile data, you can make and receive calls and video chats just as you would in your home country. You won't need any special workarounds like VPNs to use these communication tools while traveling in Slovenia.
An eSIM provides a convenient way to get mobile data for these calls. It automatically connects to the strongest available major network in Slovenia, ensuring you have a reliable connection for all your communication needs. The specific network your eSIM connects to can vary depending on your plan.