I think that may be a slightly different thing than groping around in the crap, at low level. VFR on top, can be delightful
It is an interesting situation, when you hit the wall of haze/mist/cloud/fog, call it what you will, press on possibly relying on a GPS
A scenario can be crossing the Channel, Special VFR, in haze. Basically it can be full IFR, and flying on instruments. I certainly find that I have to do one or other - fly on instruments ensuring scan remains there, with a nominal check on the magenta line, or partial visual, looking at GPS, and perhaps other aids tuned in. I do find it difficult to instrument fly, and attempt to follow a GPS. That may well be me however and my cockpits config, also hand flying as a pose to auto.
The poster did the correct thing in RTB, and again recently I hit the same scenario flying off Lands End. Clear VFR at Newquay, past St Ives, then a wall at Lands End. Heavy IFR if I had ploughed on. Turned back. Scilly Isles another day, and they were giving reasonable VFR.