There is no one answer to this question. Polyamory is exactly as much or as little work as monogamy is. While it may sound strange to you if it is a new concept, polyamory is just a different kind of relationship, but it’s still a relationship.
Some people ignore their relationships, or take them for granted, or just coast along even when they aren’t happy. If you do this you might say that your relationship isn’t a lot of work.
It would probably be harder to do this if you are polyamorous and have several partners (there’s a greater chance someone will call you on it). But it’s not impossible, and some people do structure their relationships in such a way to avoid confrontation and commitment.
On the other hand, polyamory is likely a greater time commitment because you may have several partners to negotiate with at any given time.
Also, polyamory is traditionally much more “in your face” about issues of boundaries, jealousy, and communication, than monogamy is.
Probably the best answer to this question is that having any kind of relationship be successful, be a place where you feel safe to express yourself fully, to grow, to take risks, and to feel at home, is VERY difficult.
The difference between polyamory and monogamy may be one more of “fit” than of quantifiable value. Meaning there are some people for whom a “poly” relationship is a better fit, and others for whom monogamy is a better way to go.
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