I haven't got enough work to do. Is that a problem?

Reaching the end of your work before the end of the week is not a problem in itself, it is a signal. It means your capacity has outgrown what the role asks of you, not that you are doing something wrong.

Most people fill the gap quietly. Some side research, tidying up something nobody asked about, a second pass over an inbox that was already clear, work that never appears on any list and never gets mentioned. That is a normal response rather than an odd one. Leisure research even has a name for the shape of it, an optimal amount of free time: too little creates stress, too much creates emptiness. Having too little to do sits exactly on that second edge. It is not a surplus of free time, it is a shortage of challenge inside hours your employer is already paying for.

What helps is using that room on purpose instead of letting it evaporate. Learning something specific, redistributing your tasks, or testing an idea of your own. Without a concrete plan it stays a vague sense that something ought to change, and that rarely changes by itself.