How can I get all gear ids from the catalog?

Ok so I need help. I want to get all 2000 gear ids from the catalog(this includes gears not for sale). I know that there is an api that helps you do it. However, It wont load all the gears which is a problem.

Now what I do is get contents from this endpoint: https://search.roblox.com/catalog/json?Category=5&IncludeNotForSale=true&ResultsPerPage=1&PageNumber=2000

So since there are overall about 2000 roblox gear and I have it to show only 1 result per page if I loop through 2000 pages it should give me all 2000 gear ids. But after one thousand it stops showing results. I dont know if there is a limit or something but I tried everything and all it does is it gives me around 1000 gear ids when I want 2000. Anyone knows whats the catch?