Problem 1: Behavior
At this point I don't understand why he does that. It's a behavior of a child who wants to have it his own way although his own way is wrong.
One might say it is...Narcissistic behavior.
If he gave me any arguments, even arguments such as "I subjectively don't like working with [technology A]" or "My boss asked me to do B", I would understand, but he doesn't.
This is deliberate. By refusing to make an official stance on what his objections are, he cannot be called out on lack of intelligence, he cannot be argued with and retains a way to dodge accountability for his decisions when the project fails (by blaming and firing everyone under him).
Vagueness is a behavioral trait of Narcissistic personality types.
He now wants me to attend a planning session "if I want", but "if I wanted" this would mean trying to enable something that shouldn't happen at all.
- If you go, you are actively complicit in driving the project to its impending failure.
- If you don't go, when this doomed project fails, it will be because you weren't a team player.
Setting of impossible expectations is also a behavioral trait of Narcissistic personality types.
If you intend to continue working under this individual, you may want to do some independent reading about how to cope with Narcissistic personality types. They are extraordinarily difficult to work with, and lack of understanding always leads to the unwary (like yourself) being cruelly exploited.
Problem 2: Pecking Order
My nontechnical boss's wanted me to start an important project.
I wrote a good plan.
Then my boss started to question every point of the plan.
My performance has been assessed as excellent, so I don't understand that.
Your immediate boss is threatened by you. You are rising through the ranks through demonstrated competence. He has clearly gotten by on vagaries, intimidation and taking credit for other peoples' successes.
As long as this appears to be your project, and you stand to get the recognition for its success, he will continue attempting to sabotage or derail you.
You will not be able to "argue" with him, period. Get that idea out of your head. It does not matter how well-founded your arguments are. It doesn't matter how weak or illogical his own are.
A strong argument could be made that masks prevent the spread of COVID. Since he would not get credit for the idea, a certain world leader refused to promote this solution. Instead, he tried:
- Denying/downplaying the existence of COVID,
- Presenting his own vague/bizarre solutions (malaria pills! inject bleach!),
- Withdrawing from the WHO,
- Restructuring the CDC,
- Suppressing expert testimony,
- ...and generally sabotaging all mitigation efforts that have proven to actually work.
And look where it got him. He fought acceptance of someone else's solution so hard it may yet kill him. That is how far these types will go to make sure they get the credit for success-- sometimes even trying to take credit for resolving problems of their own creation!
It is important to him that he gets the recognition for the success of this project. If he can't get the validation he feels entitled to, he will see to it that nobody gets it and you are instead condemned for its failure. People like him really are that childish. They take to positions of greater power like leeches to blood.
If you can re-present this to him and sell it in such a way that if he listens to you, he will come out of this with a promotion, you will be given a blank check to run this project however you please. You'll have to give up any claims of credit for for it...but that is a predictable outcome when you are subject to a pecking order.
(Don't make the mistake of thinking doing favors this will net you a powerful ally. It will not. Once your project succeeds, he reaps the accolades and the "high" of validation wears off, you will be considered disposable again.)