A series label system can make related videos recognizable, but it should leave enough room for each episode's subject. Consistency works best as a small set of repeatable rules.
Define the stable elements
Choose a typeface, a general label position, and a limited treatment such as a panel or outline. Record those decisions in the design template. Leave the wording and subject image specific to the episode.
Plan for exceptions
Test a short label, a longer label, and one containing numbers. If the system only works for a single phrase, adjust it before producing many thumbnails. Avoid shrinking text unpredictably from episode to episode.
Review the collection
Place several exports together at equal size. Check whether the series feels related while each image remains distinguishable. If every cover looks identical, vary the subject framing or meaningful accent instead of abandoning all consistency. Keep the template editable so improvements can be applied deliberately to future work.