Cloud apps fail if you lose cellular data or Wi-Fi. Offline apps function perfectly in remote areas, on airplanes, or underground.
ACR is arguably the most popular and reliable option for offline recording. offline call recorder app for android
On rooted Android devices or devices running manufacturer-specific ROMs (e.g., some Xiaomi, OnePlus, Samsung One UI 3.1+), call recording may still work natively via system APIs. However, for non-rooted stock Android 11/12/13/14, offline recorders are unreliable. Cloud apps fail if you lose cellular data or Wi-Fi
Disclaimer: Always check your local jurisdiction's privacy and wiretapping laws before recording any conversation. Why Android Makes Call Recording Difficult Samsung One UI 3.1+)