Hi Minh
No you are not overthinking but you are applying your own values to your ENT who may not have your social skills. It is very clear from your level of support of others that you are highly empathetic - something your ENT clearly is not.

I think the other ENT is worried about treading on your original ENTs toes but if you push, and if give your reasons, maybe the other one will relent.

The other idea is to go to another healthcare professional for advice around general stuff that is not strictly in the ENT's area of expertise. Your GP? nurse? counsellor? who can act as your co-ordinator/go betwen and listen to your concerns? Your GP may know nothing about cancer treatment but will know heaps about depression, fear and the importance of knowing what all your medications are and be much more likely to refer you on to the right person.

I have no idea if you have trismus but I can get 4 fingers into my mouth (hope the neighbours aren't watching) and I haven't had oral cancer. The bits I have read about trismus talk about exercises to prevent deterioration which in turn suggests you need a referral to a speech pathologist.

Keep pushing to get your own way Minh, it is your life and you have every right to service that you are confident about and comfortable with.