I find the first few vapes of the day are pretty harsh. I can't really take full drags initially, but it's not as bad as it used to be. By the end of the day, I'm slowly emitting huge plumes with no issue. You should get used to it pretty quickly.
But there are a few things you can do to reduce the throat hit. You can get a slightly higher-resitance carto for a cooler (albeit weaker) vape. Or you could try a bottom feeder like the kanger T3 (the coil is located at the bottom, so the vapor has time to cool before it reaches your mouth and they already have a cooler vape to begin with because they are also higher resistance than I'm guessing your DC is.)
The best thing you can do is change your juices. Up the VG percentage a little and drop the nic to 12mg. PG and nicotine are what give you most of that throat hit. VG gives you the smooth, thick vapor. Too much VG may not work too well with that setup (though otoh if it's putting out harsh vapor, it may be hot enough to vape high-vg juice w/o clogging,) so 70/30 or 65/35 would probably be about as low as you'd want to go. 60/40 could be too much.