I have visited three of your four countries, and for context, I am a very experienced, confident, savvy frequent solo female traveler.
India - Delhi: I found I could not wander around to explore, it's an enormous city that really isn't suited to wandering. I managed to get around well enough using the public transport system, tuk tuks and taxis - the places I wanted to see were so far apart. I was frequently stopped in the street and around by people wanting selfies with me, no attempt at physical contact, just a lot of selfie taking. Never felt unsafe, just sometimes a bit frustrated at being interrupted.
India - Jaipur: Same situation with the selfie taking (I actually had this all around India), but found it easier to explore independently. I used tuk tuks to go from place to place. Much nicer than Delhi.
If it's useful to know, I found Udaipur very enjoyable and happily wandered around there for days, really safe and easy town to visit.
Marrakesh: First time I went with a male partner, no trouble at all, very enjoyable. Subsequent visit as a solo female traveller, was constantly harassed and groped just walking down the street, even though I was dressed very respectfully. Hideous experience. Would never go again.
Istanbul: Have not been here.
Egypt - have only been to Cairo and for work as a solo female: Awful experience, male colleagues assumed I would be having sex with them because they believed that's what western women did. Had them turn up in my hotel room (hotel let them in!). Was warned by hotel staff not to wander around outside alone so didn't even attempt it - there had been high profile attacks on western women by Egyptian men in the recent years before I went. Would never go to Egypt again.
Sad to say there are places in the world where men's opinion of women, particularly of western women, is rock bottom.
With India I was seen as a Z-list celebrity, it was more interest and attraction, with Marrakesh and Cairo I was seen as a prostitute.