Why it only buffers in the evening

Between seven and eleven the whole neighbourhood shares the same capacity. Your router sees more neighbouring networks than it does at noon, and on the 2.4 GHz band they sit on top of each other. You notice it as short stalls every thirty seconds, always at the same time of day.

Do this: start the same channel on two devices at once. If both stall, it is the network. If only one does, it is the app or the device. The next step is an ethernet cable to the device you watch most — that solves the majority of the cases we see.

If no cable can be run, move the TV to the 5 GHz band and put a mesh node in the same room. Then raise the buffer one step in the app. Never lower the picture quality first; that hides the symptom instead of removing the cause.