One limitation of Android is that it doesn't allow you to record videos larger than 4GB in size. Any bigger than that and your video gets split up into multiple clips. The good news is that that may change with Android 11.
With Android as it currently is, the MediaMuxer and MPEG4Writer classes that are responsible for combining video files and saving them as MP4 files support outputting with a max file size of 2^32 – 1 bytes, or around 4GB. A new commit in the AOSP gerrit (via XDA-developers) shows that Google is updating Android's media classes to remove that 32-bit file size limit and instead use a "64bit offset" in MPEG4writer that will allow you to "compose/mux files more than 4GB in size".
In the commit, Google says that it successfully composed files around 32GB in size, and in one test it even filled most of a phone's memory with a recording.
This commit hasn't been merged yet, but it's expected that the change could be implemented in Android 11 since that's the next major release of the platform.
The 4GB video file limit was set in 2014, and obviously a lot of things have changed in mobile since then. Now there are tons of phones on the market that can record 4K video, which wasn't the case back in early 2014, and many devices have hundreds of gigabytes of storage space built-in. There are even some models out there with 1TB of built-in storage.
As more folks are relying on their smartphone as their only camera and recording more and more in 4K, the ability to save one record one long 4K video on your phone and have it save as one file would be a welcome change to Android 11.