I am very emotional at times too, especially when I feel an injustice has been done. I don't know your current circumstances, but I would advise not to read into this leadership change too much. Especially in racial terms.

It sounds like the incoming team indeed thinks of itself as superior in some respect. That's a dangerous way to think (regardless of whether race is involved), because they won't be able to learn anything if they've already disregarded the thoughts of those that were around before they showed up.

It also sounds like they are a bit more conservative ("convoluted code review processes... based on jira tickets") and perhaps a bit more authoritarian ("standard that must be followed for EVERYTHING").

Those may or may not be traits that the company needs to succeed at this point in time, but you're certainly not required to accept them or agree with all of them.

And you shouldn't be made to feel like a child if you've built the foundation of the product. It is disrespectful.

So you just need to ask yourself whether its worth it to try to work with them or just move on.