Like said above there are 2 types of vaping DTL which is direct to lung like your sucking on a straw directly into the lungs then MTL which is like you were smoking a cig where you draw into the mouth then inhale into the lungs, the device you have seems to be more of a DTL type device, and at 6mg strength with that it could be harsh hence the coughing, the other cause of your coughing is possibly that because your vaping and smoking, dual fuelling, I found this when trying to transition to vaping, I managed to persevere with vaping, had my last cig on a sunday night then said to myself no more and went to vaping
There are 2 different types of nicotine, one is freebase nicotine which is what you're using at 6mg strength, this will provide a better throat hit like smoking a cig, which is why I asked if it's the nicotine you're craving or is it more to replicate smoking the roll up
The other type is nicotine salts which is a much smoother vape and gives virtually no throat hit but delivers the nicotine to your body faster and allows you to vape higher strength nicotine without the harshness
Nic salts worked for me as I didn't get on with freebase nicotine (tickled my throat and made me cough), and is what finally got me off the cigs permanently, I'm still on nic salts using 3mg strength nic salts in my DTL devices, and 20mg strength in my MTL/pod devices but everyone is different and what works for me may not work for you /others
My advice would be to get a fairly cheap pod / all in one device and try a couple of 10ml bottles of juice, you already have some 6mg juice so maybe try some 3mg, and I would also try getting a 10ml bottle of 10mg nic salt juice and even a 20mg bottle of nic salt juice and experiment with them and see how you get on
Ecigone have some items on sale this weekend and also have 10% off all juices too (already discounted)
https://ecigone.co.uk/collections/weekend-offers?omnisendAttributionID=email_campaign_5ec924098a48f70e06453e70&omnisendContactID=5e4534d2bac16e1979ec49cd&omnisendScopeID=5e4530d94c7fa47e7cb55e04_2_30270029869&utm_campaign=campaign:+SPECIAL+WEEKEND+OFFER!+(5ec924098a48f70e06453e70)&utm_medium=email&utm_source=omnisend
Pod / all in one devices suggestions from me would be
Artery pal 2 pro, they only have the monster squad colour left in stock but good device for £15 and you get 2 coils with it, 0.6 and a 1.0 ohm coil
https://ecigone.co.uk/products/pal-...7&_sid=5d9c2d67b&_ss=r&variant=32140004851757
If ordering from here the artery pal stick is also an absolute bargain at £5 as you get 2 coils with it too same as above I would also throw one or two of these in there too for that price
https://ecigone.co.uk/products/arte...1&_sid=5d9c2d67b&_ss=r&variant=32139727929389
Another one although I've not tried it for £20 and you get 2 different coils to try with it is the hellvape grimm device, you can also use the artery coils from above devices in these and visa versa
https://ecigone.co.uk/products/hell...3&_sid=6c380c54c&_ss=r&variant=32140223676461
Nic salt liquids have a look and see what flavour you like the sound of and maybe choose a 10mg strength and a 20mg strength
https://ecigone.co.uk/collections/nic-salt-e-liquids
@DeeDee may have some suggestions on salts but I would say out of the selection on there you wouldn't go wrong with some from supergood, twelve monkeys (kanzi) I've heard is good, strapped salts (sour apple refresher is good) or dinner lady salts
Additionally another place I use for salts is here they usually have a good selection with cheap prices, they also have 10ml freebase liquids too
https://www.vapeandgo.co.uk/
And finally I would recommend having a look at the new users section of the potv forum and having a good read on there which will educate you alot in terms of vaping and information
https://www.planetofthevapes.co.uk/forums/new-users-corner/new-user-questions-and-discussion/
And especially
@MrDJ list of trusted eliquid and hardware suppliers
https://www.planetofthevapes.co.uk/...of-trusted-e-liquid-hardware-suppliers.78467/
Hopefully that should keep you going for a while and good luck with it all, hopefully we can get you off the stinkies