I’m facing the same dilemma. In my opinion PC or phone based tools are unreliable because we don’t have much control over their multitasking and this will undermine the resolution and repeatability of our tests. One approach that I think is viable is a Raspberry Pi based, dedicated tool. The hardware is inexpensive and accessible, allowing us to deploy probes at multiple sites for a period of days. Such tools might already exist. I haven’t researched this.