Limit and Load more

I want to use WordPress for my blog. I installed it in my local machine. It has RSS feeds with links. But I have 2 confused problems.

– I want to limit the number of results when load RSS feed with a request’s format as:
>https://[myblog_domain]/%5Brss_name%5D?limit=25

to limit to top 25 results. May be 25,30, 40, … or any integer for the limit parameter. I know there’s an option in Setting/Reading/Syndication feeds, but it’s not my expectation. I want to place a parameter in the request, not only a default number.

– Another problem, I want to load a range of RSS items with a request’s format as:
>https://[myblog_domain]/%5Brss_name%5D?oldest_known_post_id=25&more_count=10

to load 10 RSS items begining from the one previous to the post_id=25. May be any integer for the 2 parameters: oldest_known_post_id, more_count.

Are there any plugins of this purposes?