I have assisted at many general anaesthetics though they were all for dental treatment so the tube is put up a persons nostril. I can see you have had your fears allayed by other posters. Please try not to worry. I always look on anaesthetists as unsung heroes they have always tended to be very calm and very clever types, I have worked with a few.
I wanted to write more about your TMJ. It is almost always related to anxiety. The anxiety gets treated, the TMJ improves. I remember being told this when I was really young and in training. I was also told by the male lecturer that it was almost always women that suffered from it. I actually suffer from it when very stressed myself though on a far more minor level.
I found one thing helped me and that was very gentle face massage it is almost like brushing your face because the touch is so light from the chin up to the joint in the slowest way possible using the back of your hand.
The other thing of note is getting in touch with Macmillan, because if you have any emotional, medical questions and financial issues then they can advise you.
I would advise not googling any random sites, look at Macmillan and NHS websites for help at this time. I loved my time working for the NHS but couldn’t stand the hours so retrained after six years.
I hope you have someone who is going to spoil you post op, no running about after just plenty of rest. Netflix, nice food, good books.