Disclaimer: I don't use Network Manager myself, so this is purely based on the reference manual and general knowledge.
Let's see what the reference manual says about these commands:
nmcli connection reload
Reload all connection files from disk. NetworkManager does not monitor
changes to connection. So you need to use this command in order to
tell NetworkManager to re-read the connection profiles from disk when
a change was made to them.
nmcli device reapply {device}
Attempt to update device with changes to the currently active
connection made since it was last applied.
From this, it seems the commands inherently do different things. The nmcli connection reload command reloads connection profiles from disk, while the nmcli device reapply {device} applies any new profile to the active connection.
It's not clear to me from the reference manual if nmcli connection reload actually applies any profile to devices, neither is it clear if nmcli device reapply {device} reloads changes to profiles on disk, but for both I would assume this is not the case (if anyone can prove me wrong, please do).
So the logical order for these commands would be first nmcli connection reload (which makes a permanent change to the loaded configuration) and then nmcli device reapply {device} (which makes a permanent change to the active connection).
It would be obvious to create an alias that does both in one command, like:
alias nm-reload='nmcli connection reload && nmcli device reapply {device}'
Again, I would also assume you can give more devices to the last command, so you can reload connections and apply them to all your devices with a single command.
