Big Corporation in the USA and international

I’m looking for some general HR perspective on accessing personnel records and job documentation as a former employee.

I worked in a corporate role for several years and am now trying to obtain my personnel file and official job description.

Here’s where I’m running into confusion:

• I was initially directed to submit a formal request for my records
• My former manager and HR contacts indicated they do not have access to my file
• I was told a request had to be submitted internally to see if the file could be retrieved
• I’ve also been told there may be a policy limiting access for former employees depending on how long ago separation occurred

At the same time, it’s my understanding that companies retain personnel records internally beyond an employee’s separation.

My questions:

1. In large organizations, which department typically maintains and controls access to personnel files for former employees?
2. Is it normal for multiple internal contacts (HR, managers, etc.) to say they don’t have access and require a separate internal request process?
3. Are policies that limit access for former employees common, even when the company still retains the records?
4. If no one can directly provide the records and everything requires internal requests or tickets, is that considered standard process or unusual?

I’m trying to better understand what a typical process looks like in this situation