The 203 is not slow with browsing and start playing on my network but all of it is wired gigabit Ethernet though. I think the 203 was pretty slow when I had it on wireless ...While it isn't there yet, the Vero 4K+ should eventually satisfy that criterion. Right now, HDR playback on YouTube is broken - it decodes the video okay, but doesn't correctly flag it as HDR. The OSMC guys are aware of the issue and say they'll take a look once they've finished transitioning to a more up-to-date kernel. At that point it may do what you need.
The actual UI is a bit clunky for YouTube, but what I do is find the video in Chrome on my phone and then "Share" it via Yatse (Kodi remote control app) which starts the Vero playing it. Works okay.
There are certain specific situations in which I use my 203 for local streaming - when I'm playing a Dolby Vision UHD blu ray rip, mainly, and also if I want to play a 480p/24 file. But other than those two situations I find browsing into the network share takes too long and too many button presses. So I use my Vero 4K+ for everything else.