S2725QC vs P2725QE: dual monitor with U2723QE?

HI all, 

I have a U2723QE and am looking into a second monitor for a dual-monitor setup. I have a MacBook Air (M2) and plan to upgrade it to a new MacBook model or mini in the future. 

I have considered S2725QC or P2725QE, and wonder if you have any experience / ideas to share.

1) S2725QC: better price, speaker, and 120hz refersh rate. 

2) P2725QE: probably better for eyes, but 100 Hz (would it make any chance?) and the price (would it be worthwhile?)

I struggled with the text clarity of other models, and it took a while to figure out that 4K 27-inch is the best setup for macbook, and I am pretty happy with U2723QE. For a second monitor, I would like to have a seamless connection of dual monitors and the computer (for present and future), as I am a pretty low-tech person who just needs a no-brainer simplicity. 

I am not a gamer, and I work at a desk. So my usage is mostly document + pdf readign / editing + internet browsing + streaming. My instinct is (1) for affordability but wonder if I need to invest a bit more for (2) or even an identical monitor. 

Please help!