As a muscovite , I will say Moscow. Msk is more "modern" than SPb , there are better education , work and salary here. Our pronunciation is almost similar , but in the moments where trere is a differance Moscow one is regarded as more correct (according to transcriptions from Russian dictionary).
What about prices on food and enetertainment. Yeah , Moscow is a very expensive city. But I was in SPb twice and didn't see a great diffrance. You have to see what and where most of native people buy. Don't let chitters lie for you! Alas , many people like do it with foreighners as they don't know what's a norm here...
Try to find friends , for example , somebody who wants to learn Turkish. It will help you very much.
The problem would be appear witha flat (as everywhere , I think). There very many m*uslims in Moscow and i know that they help each other . You can also try to ask local diaspora for a help.
Moscow and St.Peterburg are two cities of incredible beauty and atmosphere , but , imho , Moscow is better for living.
As a foreigner who will learn in Russia too, I prefer St.Petersburg, because not so expensive and you will love the city. Even the weather sometimes bothered you, such as rainy or so, but it is worthed. Beside it you can visit many places easily there, so I suggest St.Petersburg :)
1 - is a transport. Airplane is expensive , rare and not adviceable. Most of people use cars and wait for hours and even days in line for ferryboat. It also influences on safe. Some people say there are robbers near the boder.
2 - Ukrainian war. As you know , yesterday Ukrainian army stepped to Russian teritory. Yeah , they were stipped in a moment , but I'm not sure if Southern Russia is an absolutely secure place now.
3 - Turkiy didn't consider Crimea as Russia. I'm not sure if you even can go there....
All in all, I advise you to go to Moscow firstly.))
Why? Dangerous. ?
I think it's not a good idea now (maybe next year or in several years)