Can I travel with 144hours twov?

I am going for a round trip to Shanghai:

Stockholm-Frankfurt-Shanghai
Staying in Shanghai for 5 days.
Shanghai-Zurich-Stockholm.

I’ve heard that originating destination and final destination can’t be the same regardless of layovers, is that true?

What is applied here?
Is my trip Stockholm-Shanghai-Stockholm or Frankfurt-Shanghai-Zurich?

Am I allowed to go for 144hours twov in Shanghai?

Thanks.