Sorry to hear your struggling mate.
I'm not familiar with the ego equipment. Keep trying to find a vape setup & juice that works for you. There are a lot of options out there. So I'd imagine you will find a setup that will work.
Once you find your setup, then you can give up the stinkies. Don't worry about it till you are worked out. It's hard enough as it is without having to worry about your vape setup.
Just remember the first 2 weeks giving up is the hardest. You'll have a lot of cravings. I found they dropped away a lot at that mark. And I rarely have them now.
Is the cough coming from within your lungs or your throat? If your lungs I think the suggestion about reducing airflow and looking at MTL (mouth to lung) type vaping may help. If it's your throat then yes you'd have to look at juices. I think, not totally confident.
If you have any vape stores where you live that would be a great way to go and try various things. Mate keep trying & posting what you are doing you will get as much help as you can take in here.