I am trying to be optimistic that they are developing GTA VI smoothly like they haveto especially GTA V was released seven years ago.
However, they are also still updating GTA/RD Online regularly so those could be taking their focus away from GTA VI.
I personally I'm tired of GTA V's map and I don't need to try every new vehicle, weapon and outfit in a 7 year old game. Like in Valhalla I already stopped collecting the free cosmetiXs. Yeah GTA V's map is still big compare to most recent games but everytime I reinstall it, I can't find the urge to play it straight for two weeks. Its like going back to a place you lived before, you reminisce the good old times but you can't find the effort to spend one more day in it. Like I am ready for anew environment already. And there aren't a lot of 3rd person open world games recently set in the modern day world.