The O6 may all be open from east of Izmit to west of Istanbul this year, certainly by this time next year. Not much is visible of the last section of O6 east of Izmit (around Adapazari ) yet. Maybe a 2021 or even a 2022 opening there.This appears to be a 17 kilometer section between Demirciler / Dilovasi and Sevindikli, which is east of Istanbul. Open Street Map also indicates this section is open to traffic.
Construction, Operation and Transfer of Menemen-Aliağa-Çandarlı Motorway Project
Yes, take a look here: https://www.openstreetmap.org/#map=10/41.0561/29.0533There is also some more infrastructure around the Northern Marmara Motorway east and west of Istanbul under construction.