Welcome to ECF. Which Blu device are you using?
In the US, they sell a pod system (My Blu) that comes in regular and intense versions with different mg or percents of nicotine in the liquid. The intense version uses a salt nic, the regular uses the freebase nic. I found that the My Blu pods hit really hard and I get the coughing and feel uncomfortable with them even at the lowest nic levels available.
They also have a disposable or tank system cigalike device. I find these do not irritate my throat like the pods, and are easier to use. I think the liquid as well as the way the tank works makes for less hit than the pods give.
If you are using what I would call a vape pen, that sounds like the old ego style device and has been gone from the US for a long time. These used a refillable tank and you could add your own liquid when it went dry.
After you have checked with a medical doctor to make sure you aren't having any medical issues from either past-covid or some other problem, you may need to try another type of device that offers more choices of liquid bases (PG/VG) and nic levels. If you are interested in some of the other kinds of vape devices, either pods or tank systems, there are many folks around here that could help you find something that works for you.