Vapor tongue is real. As others mentioned, taste buds take time, sometimes a long time, to recover, but improvement is noticeable over time.
One trick I learned from some of the flavorists that mix our flavorings is that they will inhale some freshly ground coffee to "reset" their sense of taste between batches and testings. I was skeptical, but tried this and it works for me. After a good oral cleaning in the morning, a good dose of freshly ground coffee, and a good delivery device, the taste is substantially improved.
Other pieces affect flavor, as well. clearomizers like the Protank have a great vape, flavor and vapor, compared with most other clearos, and the PTII may be the best clearo on the market at the moment, imho. Another issue is the wick material, silica sucks to me now, after rewicking with cotton. Even the type of cotton makes a huge difference. I ordered and fell in love with some organic cotton balls that I found on Amazon. The are cleaned and bleached with hydrogen peroxide, so they don't get any more organic than that, though I still see videos where they recommend boiling the cotton. I don't, and don't need to as I cannot taste any other "flavor" with the cotton balls I now use.
Clearo's do mute the flavor compared with other devices. Carto tanks are a huge improvement in taste and vapor over clearos, imho, and after six months of evods and Protanks, became my ADV. Some people claim they can taste the filler material in cartos, and don't use them. Sorry for them as cartos are my favorite, but also glad for them if they can taste that well.
Recently, in the last few months, I have working with RDA/RBA's quite a bit. At first, I didn't notice any difference between them and most clearos, but since I upgraded to the best cottons with good kanthal wire (not nichrome - bad taste to me), and began experimenting with different coil setups for the Ithaka, RSST (genny) and the Kayfun (my favorite), changing resistances, I finally discovered a huge difference in flavor improvement over the cartos. I've heard, but haven't yet tried the HH357 atomizer is great, and my drippers have taken a magnitude better flavor for me. The lower Ohms, say 1.3 - 1.5 seem to give me the best flavor. I can taste juices and ingredients that I never could before, even with my cartos. Airflow can affect the flavor greatly. I recently added the Kayfun 3.1 to my Kayfun Lite and with a tighter draw (my preference), I get the best vape of my life. Part of this is likely my evolving/improving taste buds.
The other thing is that finding an all-day-vape (ADV) is very difficult. I DIY and find a new ADV about once every two months, and I experiment with juice every weekend, and steep like crazy. The more complex flavors can take literally weeks for the flavor bonds to fully form, and the very subtle ingredients to be perceivable. Like many others, chasing the best vape is a passion. The more things I try, the more discoveries, and sometimes, the better my vape gets. Also, a well-known maxim is the PG/VG ratio. I use a 60/40 mix (60 PG) and that is my sweet spot with cotton. This is my RDA/RBA coil setup/juice. I use cartos, though, still on a daily basis, primarily for the quality of vape and ease of use. I haven't use a carto longer than three days in months, as I don't like any diminishment in the quality of my vape, not even a little. So, in summary:
FACTORS AFFECTING FLAVOR
1. Device type (clearo top coil, clearo bottom coil, carto, dripper/RBA - in that order [worst to best], imho)
2. Wick material (cotton is the bomb, organic cotton preferred). Not going to discuss mesh, diapers and what have you on this post. Go cotton!
3. PG/VG ratio (PG carries more flavor, VG more vapor - I prefer a 60 PG/40 VG ratio)
4. Air flow is critical. An air flow controller for a clearo makes the Protank variable and better ($3-$4)
5. Atomizer resistance
6. Juice and steeping time
7. Clean and clear the palate (hygiene and "reset" with aroma of freshly ground coffee)
8. Change juices. This can reset the palate. If I vape a Danish all day, I switch to a fruit, and my buds come to life
9. Coil temperature, closely related with Ohms. Every juice and coil assembly has its own "sweet spot". Experiment. You must have variable voltage/wattage to get the most out of any vape
10. As Bad suggested, try different juices and toppers until you find what works for you. VapeQuest is just that, an evolutionary process to find what works best for you, and this changes as your taste buds change. Watch lots of device specific videos and learn how to get the most from your toppers and juice.
11. Change coils frequently. Cleaning and dry burning helps, but a fresh coil is always better, imho. I never used clearo coils or cartos after three days. YMMV. This keeps it good for me.
12. Topper materials - I prefer stainless over most other metals. I prefer pyrex glasses over most plastics in tanks. Experiment and find what works best for your juices.
13. Taste buds do come back to life over time, and improvements in taste, smell and flavor does improve over time and does become noticeable. Be patient. It may have taken years to "kill" these senses. It will be a while before they fully recover.
Good luck, happy JuiceQuest, happy VapeQuest, Power up and Vape On! Welcome to the Forum. Best to you!