I can attest to what SteveS45 said. Flavor concentrates to make diy juice with are potent. I've knuckle tested some and it usually makes the tastebuds spaz. I'm talking just a tiny amount like enough to just barely make the skin glisten, not even a 'drop'. lol.
As far as juice tasting the same vaping it as knuckle testing, I've found it's stronger tasting the ejuice itself. Which makes sense. You're getting just the flavor. When vaping you're just getting the 'steam' of the flavor with a lot of air mixed in. Like cologne, smelling it in the bottle vs applying a small amount to the skin and letting it waft through the air. Worn it's a lot milder. The heat from the coils can also alter the flavor some, bring some flavors out you may not taste cold. Should be similar at least.
Other things that can affect flavor, the coil itself. I find I get much better flavor from stainless or nichrome wire over kanthal. Kanthal to me is like taking whatever ejuice you've got and cutting it with about 60% water. Just muted real bad. But that's me and flavor is subjective, some people prefer kanthal to stainless or nichrome or prefer nichrome to either stainless/kanthal. You said 'tank', not sure if you mean rta or subohm tank with factory coil heads. Not all but most factory coils use kanthal by default. Though it's been changing, more and more are using stainless, nichrome or mesh.
If it's an rta, coil placement can impact flavor. Type of coil, paired with type of rta. Like I wouldn't try to stuff an alien coil in a kayfun rta, or run a small 2mm simple round wire coil in the ammit rta. In bigger rta's that have the room, I prefer the taste of fused claptons over twisted or simple round wire. Again subjective, some people are all about simple round wire coils. To me even a basic twisted coil is a big improvement over simple round wire in direct lung rta's. Kayfuns or other smaller chambered single coil mtl/restricted direct lung types thrive on simple round wire coils.
The design of the tank can impact flavor. Not pitting brand against brand since both are copies and not authentic, just comparing their general style. I've got a kayfun v4 and kayfun v5, also a taifun gt3. The kayfun's are almost identical aside from a slight airflow difference between v4 and v5. The taifun deck is almost identical, simple 2 screw setup for a small single coil. Chambers are about the same size, chimneys are about the same size. You'd think running the same identical 2mm or 2.5mm id 8 wrap spaced 28ga ss316L coils from the same wire spool that flavor would be similar. Nope, not even close. The taifun lacks flavor something fierce while the kayfun types are rich and full of flavor. Doesn't matter which is which other than it proves two tanks that are 90-95% visually similar can have two very different outcomes. Whether it's the shape of the bell inside the chamber, chimney diameter, how the air enters the rta.. both have a single small round air hole beneath the coil so it's not bottom vs top airflow. No idea but they definitely differ in flavor. One's great the other tastes like nothing but warm air.