Inspiron 14 4525, resolution on additional monitor

Hi everyone,

I'm buying a secondary laptop and monitor for occasional use at business events, I'm looking at the Inspiron 14 5425 (cn54406) with the AMD Ryzen 5 5625U processor which comes with Radeon Graphics.

I appreciate that the maximum resolution output via HDMI is 1920x1080,  but the laptop also supports DisplayPort via the USB-C port (using an adapter). I'm struggling to understand how I can find out the maximum resolution available via the USB-C/DP port so I don't waste money on a monitor with a high resolution that won't be supported.

I was hoping to buy a 24" monitor - is that too optimistic with this laptop and it's onboard graphics?

Finally - on audio - when the spec refers to "headset jack" - does that mean it's a single 3.5mm jack port that will support wired earphones with an integrated mic on the cord?

Many thanks for your assistance.