personally, I would find new developers.

It is really simple. Page one would have products 1 to 500 and page two would have products 501 to infiniti.

Of course my numbers are purely for example, but the concept is simple.... Split the products up on the pages.

Also, creating unique meta description, content and title isn't a big deal.

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But for the actual question...

Duplicate content is worse... Why?

Because bounce rates can be fixed by making the landing pages more user friendly and helping visitors find what they are actually looking for.

Where duplicate content can have a negative impact on your rankings, so the visitors will never even find your website.