Start with
a little clarity.

No. Latency, packet loss, request dependencies and server processing all contribute. The right measurement follows a representative action rather than a single large download.

It can reveal a symptom. Repeated observations from relevant locations make it easier to distinguish a persistent bottleneck from a temporary or local condition.

No. The round-trip calculator is a local estimate based on the values you select. It does not measure or scan your network.

Record the affected application, location and approximate time. Note whether the behaviour is continuous or intermittent, and compare another network when possible. Keep passwords and private access links out of diagnostic notes.