Conditional trigger to activate --external-downloader

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• I've looked through the README
• I've verified that I'm running yt-dlp version 2022.09.01 (update instructions) or later (specify commit)
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Hello,

I Would like to suggest a new feature for yt-dlp, if accomplishable or viable to be done.
After made this question on r/youtube-dl, seems to me that this is not possible yet.

The context is:
When using --external-downloader aria2c --external-downloader-arguments "-x 16 -k 1M -s 32" for large files like videos, the download speeds increases greatly, but for small files like audio, it becomes slower compared to the native yt-dlp downloader.

What do I have in mind:
The idea is to implement a new flag, for example --external-downloader-trigger 50M and yt-dlp would use aria2c as external downloader only if the desired file to be downloaded was greater than 50mb; otherwise it would use its native downloader.

Possible use cases:
This is useful in the scenario of user automation, like a batch or bash script for example, or mentioning my use case, I'm using AutoHotkey to download videos and audios from YouTube when pressing a key combination.

Additional information:
It is important to consider that despite it can be done programmatically at the script, most people are not so good at scripting like professional devs are.
I think it would be necessary to check the size of the audio or video at the desired format to be downloaded, this seems complex to me.
So, implementing this conditional trigger can be challenging for people who are laymen in programming. If yt-dlp could bring it to us natively, it would be a great addition to its features.