No — treat them as a starting skeleton. Swap in themes that better match your niche's specific seasonal moments, launches, or audience events.
Plan themes a full year out, but only script/produce content 2-4 weeks ahead. Planning too much detailed content too far ahead makes it hard to adapt to trends.
Build in slack — treat the monthly number as a target, not a hard requirement. Missing one month is far less damaging than burning out trying to hit an unrealistic volume every month.