Short journal · Original editorial · Observation before explanation
A page feels slow on one device during one visit.
An explanation should not erase the observation that prompted it. Record what happened, under which conditions, and what you still do not know. A plausible interpretation can remain a hypothesis while you decide what would help distinguish it from alternatives.
Record the conditions before naming a single cause.
Try the change once before turning it into a permanent routine. Keep the part that helps and revise the part that does not.
Try a question
What would you notice after trying this in one small, real situation?