To use 4K screen the best scaling in windows 10 is exactly 200%! Nothing between. Only with that scaling it is guaranteed you see the HDPI-Option in Studio One without artefacts. With HDPI on, Studio One is not streched like any older DAWs, but it will use hi-resolution picture, lines, lanes, fonts, circles etc... the whole GUI is twice that big.
If VST plugins can not do this.. means, if they arn't provide or support any HDPI or high resolution mode, then the just stay tiny. There are a few modern plugins that looks perfect in 4K. e.g. the great compressors from Klanghelm. Or the Juno Synthesizer from TAL. We all can hope, that other developers and comanies will follow.
Because it's a fact for me, that HDPI will be the future!
And Studio One is ready for this!
Further informations you can read in our blog with this topic.