Is the Dell S2725QS monitor compatible with the Mac mini M4?

Dell – Dell 27 Plus 4K Monitor – S2725QS

This is a 27" monitor with a resolution of 3840x2160 pixels. It has

• Two HDMI v2.1 inputs which support a refresh rate of up to 120 Hz
• One DisplayPort v1.4 input which supports a refresh rate of up to 120 Hz

I'm pretty sure that you could use this monitor with a M4 Mac mini or M4 Pro Mac mini, using

• A HDMI to HDMI cable
• A USB-C to DisplayPort adapter cable
• A USB-C or Thunderbolt hub or dock that has a HDMI or DisplayPort output. Note that Macs can drive one display over a plain USB-C hub or dock; up to two over a Thunderbolt one.

Either Mini should be able to drive that monitor at the full 120 Hz refresh rate from its built-in HDMI port. The tradeoff for the high refresh rate would be that you would be limited to one additional USB-C or Thunderbolt monitor, instead of two. I'm not sure if you would be able to get 120 Hz over USB-C.

You probably can skip installing the Dell Display and Peripheral Manager for Mac software, unless it has some feature that you really want.

In addition to the excellent support and advise that Servant of Cats has provided.

Have a look at > Connect a display to Mac mini - Apple Support