After my recent find with the first loading problem and solution here, I've tested out both VST2 and VST3 2.0.3 rescaling functionailty. VST2 shows the handle, but when I try to rescale in Cubase 9.5.40, the handle works and I get a white 'refresh' area but the window seems to 'fight' with me and keeps trying to scale to smallest possible window size. When I release I get a small (like pixel small) window for the synth so I have to close it, reopen it and the view resets back to original size - so resizing doesn't work correctly on VST2 64bit for some reason.
VST3 64 bit 2.0.3..... now we're cooking. Works superbly, scales in real-time and fills up a 4K screen so well. On closing then reopening VST3 remembers the size and position on screen so there's no issues there.
Once 2.0.5 is repackaged (to house the VST3 64bit version instead of the 32bit as per this link) I'll test both VST2 and VST3 for rescaling. If VST2 fails in Cubase I'll try in Reason and see what that does (might work differently), and will test other DAWs (got a fair slew of them... Reaper, Studio One, Samplitude, Waveform, Harrison Mixbus, plus I can test in Soundforge for the FX as an insert to see what happens in that).