Oh god OP some of what you have written could have been written by me. You are in a bad place and you need to walk away from this man now.
Eventually he said that his honest opinion is that I’m not ready to do the new job. This really hurt because everyone else thinks I’m ready or will be by the start date.
This is shitty. It is MASSIVELY undermining. Ask yourself why he is saying this to you. You have said yourself this is a big deal for you because (ready or not) you have saved yourself a newly introduced compulsory year. Someone senior in your profession would be cheering for you. If they had YOUR best interests at heart, even if they suspected you weren't ready, would not be saying that they'd be saying they would support you if you needed help.
You've got the job. He knows you won't turn it down because of what he says - so the ONLY purpose achieved by him telling you he thinks you aren't ready is to make you feel lesser and unworthy and question yourself.
Of course you were hurt. Why do you think he said it? He's not stupid. He's doing it to cut you down and make himself seem bigger, older wiser. It is nasty nasty nasty.
Same for what you said about his comments about your nice Whatsapp photo.
He said that despite him being so exasperating I still keep coming back for more punishment.
This is HUGE red flag. He is saying he knows he can treat you badly undermine and eg hurt you by suggesting you aren't up to your new role professionally. But he knows you aren't going to walk away. This is such a bad sign it's off the scale of bad signs.
I think he’s used to women submitting fully or just not being interested so I think he’s enjoying the dynamic too. When we’re together it’s like we both come alive. Cheesy I know.
I'm sorry to be so brutal but its because I see myself in you. You are absolutely kidding yourself if you think you are not submitting fully or are pushing back or creating some new dynamic for him. You are totally deluded.
Just read what you've written here. You've got a man who undermines you professionally and how you look (These are the two examples you've written about but I'd bet there are many more), doesn't reallly ask you out or text you that you are bascially doing all the leg work with and occassionally you make a mild fuss about him behaving like a cock. You see this as a pushing back non-submissive dynamic. You are really deluded. It's about a submissive as you can get short of lying down on the road with a sign on your head saying walk all over me.
I know whereof I speak because I've bloody well been there.
Wake up and smell the coffee.
If you get off on being treated badly or dominated because it feels safe and familiar to you, then that's what's going on here. Either admit it to yourself or get some therapy.
Confessing it's so easy to see in other people but harder to fix in your own life.