Http, http 2 & http 3 allow you to use the same connection for multiple requests.
Often many podcasts are hosted by the same provider.
Does AntennaPod reuse open connections to asynchronously load files and upgrade connections to the highest http version?
Bundling multiple requests doesn’t make a difference for large media files. It is just a tool for many small files like on websites.
Getting the feed and images as well as subtitles could still benefit from higher http versions even if the benefit for larger files isn’t that big.
It doesn’t make any difference for AntennaPod 
Just do the math, a round trip takes a few milliseconds…