[obstacle1]

> This doesn't explain why they wouldn't accept the offer of work from /u/lopkeny12ko

It sounds like OP is moving a bunch of the startup's systems onto bigcorp's infrastructure. Usually you can't "just do" stuff like that in a public company since there are laws and regulations surrounding access control, change management, data security, etc. For example PCI, SOC2, SOX, GDPR, ...

It's usually not the case that the bigcorp people just want to prevent the fast-moving Startup Superstar! from moving quickly. Bigcorp operates in an entirely different context from startup, and needs to protect itself from employees with incomplete information making reckless decisions.

I agree that OP should find a job that's better suited to their preferred style of working.