1. His mystery series are always popular.
2. His mystery soap operas are always popular.
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Does #1 mean #2?
1. His mystery series are always popular.
2. His mystery soap operas are always popular.
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Does #1 mean #2?
3. When I start writing a new series, I usually stay up late for days.
4. When I start writing a new soap opera, I usually stay up late for days.
[Does 'series' mean 'soap opera?]
A series can consist of topics including soap operas and other themes. There are police-drama series, law series, doctor series, and others. So no, "soap operas" and "series" are not interchangeable.
https://www.imdb.com/title/tt0106079/?ref_=nv_sr_1 and https://www.imdb.com/title/tt5290382/?ref_=nv_sr_1
https://www.imdb.com/title/tt1442462/?ref_=nv_sr_1
https://www.imdb.com/title/tt0413573/?ref_=nv_sr_1
No, statement #1 and statement #2 do not mean the same thing. Although both statements mention mystery series or soap operas being popular, they are not interchangeable.
Statement #1 says "His mystery series are always popular." This means that the author's mystery book series consistently enjoys a high level of popularity among readers. It refers specifically to a series of books belonging to the mystery genre.
Statement #2 says "His mystery soap operas are always popular." This means that the author's mystery-themed soap operas are always popular. It refers to a specific type of television drama that combines elements of soap opera storytelling with a mystery plot.
While both statements discuss popular mystery-related works by the same author, statement #1 refers to book series, while statement #2 refers to television soap operas with a mystery theme. Therefore, they do not have the same meaning.