Commit Diff Response File limit Restriction

Commit Diff response is not complete.
I have committed 2k files in a single commit. However on using the api
https://gitlab.com/api/v4/projects/project-id/repository/commits/commitId/diff
with a page limit of 20, I am able to get only upto 1600-1620 commits.
The last page mentioned is also only upto 82 when per-page limit is 20,
on using perpage limit of 100 also the last page is only 17

Is there a restriction on the commit-diff? Is it configurable?
Is there any solution to get all the files in a particular commit (no limitation).

Can someone help with this with any work-around