A NBT tag for entities to dynamically keep the chunks they are in loaded

This would be crucial for players and mapmakers to create autonomous structures and, in case this other request gets "adopted" by Mojang, allow long-range autonomous railroads to exist in the game, without needing to use mods/plugins or spam /forceload for large pieces of terrain, what can be disastrous performance-wise for both dedicated servers and also in singleplayer environment.

There's a very interesting essay about this on Reddit's community for Minecraft suggestions that offers more details about how it can be implemented, but since i don't know if that space is considered by Mojang when implementing new features, i decided to bring that idea to this official channel to get better visibility, and also to complement the other idea about revamping minecarts to form trains.