Quick background: Me and my wife both work from home sometimes, and are both used to two or three monitor setups while in the office. For our home office I would like to have a universal laptop dock (our work machines are from different manufacturers) connected to three monitors. Ideally these would be MST compatible so I can daisy-chain them together, not only does this limit cable messiness but also means if we get a home computer in the near future then it will be much easier to switch the video output between laptop and tower.
According to the featured products page on the DisplayLink website there is only one product with 3 or more video outputs at the moment, the Dell D6000.
The Kensington SD3650 is based on an older chip only supporting DisplayPort v1.1. I think I have a very similar device based on this chip and it doesn't work with MST. My Dell U2515H is also a bit unreliable with MST but your mileage may vary with newer products. At worst you'd have to go back to connecting 3 displays to the dock separately, 2 through DP and one through HDMI. It may be a wiser choice to plan for that and capability to output at least WQHD.
I can't find details in the manual about MST support or the supported DP profile level, but it should work.
Since you're not going for monitors that use USB Type-C or Thunderbolt 3 for video, USB and power you will still have a few cables at the desk and some of the better DP cables are quite thick. Sorry but I don't think you can get a reliable solution on the market today. I'd love to see it too, and also compatible and affordable KVM switches.
Final note: if you are using f.lux/redshift you may want to check. I think I saw a comment by the f.lux developers that they got it working with DisplayLink chips after years of having no support, but I haven't checked since.