I guess you are asking for opinions (since there are no studies comparing the safety of direct lung inhaling versus mouth to lung that I am aware of.)
My OPINION is that if you are trying to quit smoking, you should take your chances and accept whatever risks we know about or don't know about with vaping.
Vaping is considered harm reduction from smoking. Nobody knows if it is harm-free (never heard anyone say it is either).
But we
do know that cigarettes are quite *unsafe*.
My story: while I was in the throes of quitting cigarettes, the first year, I vaped how I needed to.
After I was sure I was off the cigs, I started to adjust the way I vaped, i.e. my goal the 2nd / 3rd year was to vape as risk-free as possible. So I stopped vaping anything with acetyl proprianol and DA just based on the studies I read and the suspicions that some flavorings "might" be inhalation risks (which we still don't know for sure) and also, based on the "less is more" philosophy of moderation (which I believe in overall for life in general) I was gradually able to vape less ml per day, etc. and put
less of everything into my (already assaulted from smoking) lungs in general.

My natural inclination is to not over-do anything, so eventually getting to 0% nic and 3ml per day has met my own personal goals. Quitting vaping at some point is on the horizon.....not sure how close or far though LOL
Everybody has a goal or desire and they should do what they think is best for themselves though.