At a part-time job, reliability is rarer than talent. Managers schedule the person who shows up.

Managers are solving a staffing problem, not running a talent contest. The person who turns up on time every week removes a worry, and that is worth more to them than someone impressive who might not appear. Talent is also invisible on a rota while reliability is recorded in it. This is one of the few advantages available to anyone who simply wants it.

Pick the next four shifts and be early for all of them. Say yes to one awkward shift nobody else wants. Then watch how the schedule starts treating you, and ask for what you want from that position.