The opposite of "more seasonal" could be "less seasonal", indicating that something is not as closely aligned with the current season or time of year. Alternatively, "out of season" could be used to describe something that is not timely or appropriate for the current season. "Off-season" could also be an antonym for "more seasonal", indicating that something is happening during a time when it is not traditionally popular or expected. A final option could be "non-seasonal", which would describe something that is not linked to any particular season or time of year, and could be used at any time.