Smart TV mp4 playback

We noticed a long startup time when playing mp4 file in web app with html 5 video element.
From our investigation, it needs to download up to 4 Mbytes of the mp4 file before playback can starts on 2018 - 2022 TVs, whereas on 2017 - 2018 just need 1Mbytes.
Is there any configuration or method to reduce the startup time?