Reading through the whole thread, it strikes me that the OP has overly complicated this by totally ignoring one piece of advice that had been repeated several times.
The OP is a very long time off gaining the two years they require to claim unfair dismissal. So there is no claim to an employment tribunal since there is no evidence that this "dismissal" relates to any of the exceptions.
Given that is the case, everything else is hopelessly grasping at straws, which, apart from anything else, even if the OP had a case (and I can't see one either) would cost them a lot of money to mount. If the OP had that much money to risk then they wouldn't be trying to hopelessly cling on to their job. They wouldn't need to work!
OP, I'm sorry but there is only a very blunt way to put this. It does not matter what your opinion of your performance at work is. The opinion that matters is your managers. And that is the only opinion the employer will care about. So you have two options. The first is that you find another job. The second is that you stick your head down and do the work to exactly the standard that the manager wants, and in the way that the manager wants. It may be too late for the latter now, but that is the only option other than get a new job.
Everyone has been been telling you this for two months, over four pages. I understand that it isn't palatable advice. I understand that you are upset and angry. And you may be right about everything - you may not be doing anything wrong and the manager may want you out for other reasons. But you must understand that none of that matters. Everything here is screaming that you are going to be dismissed. And you are clinging to an invisible thread that says you might be able to sue the employer. You can't. Simples!
Please, for your own sake, listen to people. Get out under your own steam before anything else happens. No matter what happens now, that is your only real option. Then move on and have a successful career, and prove them wrong with it. But you can't prove them wrong now - that boat has sailed.