As the bottom of
https://support.google.com/feedburner/answer/79626?hl=en indicates,
just provide Feedburner with an Original Feed with more posts.
Though have to ask, for what purpose ?
Anyone wanting all you posts to be visible in their respective feed aggregator
would already use one of your Blogger feeds and select to show more posts, such as
is ~875 KiB, pretty close to the 1 MiB limit
, which currently has 153 posts, would be well over the limit by the time you hit 200 posts.
on the other hand could remain well under half the maximum allowed size by the time
you reached 500 posts - the maximum number of posts Blogger can provide
per feed URL with the BlogID based feed URL -
after which one would have to start using the start-index parameter to get the next 500 posts.
Of course, as a summary feed, it would not have images or videos visible in the feed,
so users would have to actually visit your blog to see the images and embedded videos.