I am no expert, but i am awake at this hour, so I will take a shot, at answering.

If you tried a "regular" ego, and had "enough" wattage, then variable voltage is not the answer. The lowest voltage is around 3.3, which is what the blue, and a ego use, I believe. Some of the newer egos are 3.7, which is not much more, but noticeable.
To me, it sounds like you should try a higher
VG content in your juices, and perhaps lower nic. VG is more "smooth",as opposed to PG, (VG also 'mutes' flavor). Higher Nic also increases the "throat hit".
Also "youtube" is your FRIEND! There is a technique to filling your own cartos, but is easily learned by watching videos on it. Just google "how to fill a cartomiser" . Cartomisers are cheap if you fill your own, and each one should last a week at least. The carto itself should last a week, NOT the juice, that you have to refill several times a day probably, I did.
Here is where I get my cartos:
510 BOGE 50MM (XL) STAINLESS STEEL 3.0 ohm CARTOMISER (Box of 5) they also sell cheap 'mini' egos that are 450 mAh, that will last at least twice as long as a cigalike, and not take up much more space.
I can't tell you much about store bought juice, because I have been making my own since my first month vaping. I too, couldn't find a juice I liked, and was spending a bunch of money on unknown stuff, because others said it was AWESOME, only to find out I HATED IT. Juice making is CHEAP, and now if I don't like something, I toss it, but that doesn't happen very often , because I know what I like at this point, and I don't experiment much anymore.
I DO want to tell you, DON'T give up. READ, READ, READ, on this forum, (this is where, I learned everything, including SAFE juice makin'.)
Don't buy everything "suggested", especially if it's complicated, and expensive, egos, and cartos, are FINE, I used nothing but for a year in the beginning.
Hope to see you around the forums, keep asking questions.
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By the by, check out my signature, and double the stats (subtract maybe $2,000 at MOST for vape equipment, and juice ingred.s). That is how much money saved, and cigs NOT smoked by me and husband in the last couple years!!!!! and NO TAR IN OUR LUNGS!!
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