* I've only briefly looked at the specs of each monitor, so please double check everything listed below.
Ideally as you have a Mac that has Thunderbolt 3 ports you want a monitor that connects directly with a thunderbolt 3 cable.
The more expensive BenQ does. The cheaper one does not support Thunderbolt 3 and you would need an adaptor and cable to convert from Thunderbolt3/USB-C connector to Display Port. I do this when taking my MacBook Pro 2020 to a facility that has Display port monitors. This works fine. (I use an Apple Thunderbolt 3 to Displayport adaptor and a standard Display port cable)
The Dell Monitor supports Display port over USB-C - so this should work as well - though again you need the right cable - check one comes with the monitor. Sometimes they don't.
The Viewsonic also supports Display port so it too would require a Thunderbolt3/USB-C to Display Port either via an adaptor and cable.
As too brands - I'm partial to Dell as they have always been rock solid for me but the others are fine too. As too size - I like bigger. However for much of my work I have a 27 inch sitting next to the Macbook Pro and this works fine. Though I like to have the Mac on a stand so it sits level with the 27" and also use a full size external keyboard and mouse.