What vsync issues? Are you talking about yabasanshiro specifically? Cause i've been using lakka for the past months both in dock and handheld a lot and had little to no problems at all. The only obvious problem i see for now (and it still exists) is related to weird shenanigans with swanstation/duckstation and pulse audio driver where some psx games slow down a lot for no particular reason and you have to switch to alsathread (which kinda breaks dock audio). Other than that, i had almost zero problems with psx, dc, n64, arcades, psp, gc and the rest.