"I wouldn't be surprised..." isn't really a strong enough sentiment to support the statement "vaping definitely isn't healthy". At the moment, the harms of vaping are speculative.
My sentiment is more about where I think the research will go.
https://www.cdc.gov/niosh/topics/flavorings/
I'd be interested to hear of more.
I was friends with a major twitch streamer who used to vape literally 24/7, every stream. He got esophageal cancer and died after fighting it for ~1-2 years, roughly around age of 23. Now, obviously this is anecdotal, and obviously it could have just been bad luck/other factors/coincidence. But, I have always raised an eyebrow towards vaping since then. The only forms I consider safer with minimal consequence is dry herb based vaping with convection heat --- See silver surfer vapes for example.