I have a magicjack for the phone in my house here in the US. It comes with an app that allows you to use your home number for traveling and it works really well in Thailand for all calls to the US. It also has texting but I don't think you can send pictures or files but it's not really necessary for me because there are other ways for those things.
I would see what visa works for you and do it in advance. Border runs and renewals are time consuming and expensive. I know 2 people that's been there since March of 2023 doing that. They sometimes have problems at immigration and sometimes the country that you do the border run charges for a visa too.
You're right. That was probably a whole different airport. I would hope things are different now. I know that Turkish Airlines now sets up their flights for people that want a long layover to explore the city. I had a 9 hour layover and I just stayed in the airport. They had a playground for the kids and we did a lot of walking which really paid off when we ended up having a connecting flight later down the road with only 1 hour and 30 minutes duration between flights.
Istanbul airport is fairly new so it isn't quite developed in the area of the airport yet. The general idea in a lot of cases is to build the airport a distance away from everything to have all of the space an airport needs to function and then with time developers start to build stuff around the airport to get some of that business from people that don't want to travel far into the city. Sorry about your negative experience.