I wondered the same thing. I also have adenocarcinoma and was diagnosed almost a year ago (2021) with stage 4 cancer. I can't remember though which came first the very small persistent cough or the COVID jab. I actually think because I was under loads of stress at the time it supressed my immune function and allowed the cancer to take hold.
Has your Dr done genetic testing on the cancer cells? Not everyone has a specific treatable mutation though, but it is one of the first things Docs try to find out. Garvan Institute are still running MoST where they do genetic testing for free but they only give you one free shot at it so you have to make sure you have enough cancer cells for the sample. It is all overwhelming at the beginning but there is stacks of info on the Cancer Council site and Lung Foundation Australia offers free support groups for people to talk online (zoom) and also a peer support program where you are matched with another person and can talk to them privately on the telephone and also there are Australian lung cancer facebook groups out there for support. There are many of us out there.
