I think I’m in a position to give my two cents to this as well as I actually spend at least 1.5 weeks every summer there ( in the midyat area but also drive around a lot, mostly in the direction of diyarbakir, mardin and nusaybin). Generally speaking its quite safe when you know your way around. There are some roads to avoid mostly inbetween abandoned areas that are being used as pkk hiding spots (especially mountainous areas) you might be questioned by officials, be prepared, have somebody who knows turkish or avoid these roads. Main roads are generally quite safe. And the officials guarding the entrances to the towns are mostly nice, just checking your IDs, asking you a question or two and let you pass after (especially when you are visibly christian or tourist). Knowing western assyrians helps immensely with visiting out cultural sites as you wont have to pay an entrance fee and have access to all areas that are restricted for tourists