Please take the time to read this, they are only a UI of truenas they have no control of the root operating system. This is not my opinion or assertion it is fact. If you have watched any of the installation videos like the one by Lawrence systems, your start by installing truenas onto your machine, then logging into the hexos portal with a machine on the same network to see the trunas installation. Therefore its not HEXOS that will need to support lower ram, its the operating system vendor. I am sorry if this seems curt in any way, but you simply do not understand what hexos is providing.
https://www.truenas.com/blog/powered-by-truenas-hexos/#:~:text=By leveraging the robust and,manage their own home servers.