Edit > Edit Preferences > Hotkeys > Edit: Save
By default it uses Ctrl+S, which makes sense for a 'save' operation.
Testing it now, it appears there are some key combinations it won't let you use, including the Enter key on its own.
It's true!!!. I hadn't thought of putting the enter key for the save as a shortcut.
It works but has a fairly serious shortcoming, if musicbee is open the enter key is intercepted in any application, even if minimized, so it does not function send anywhere. It is necessary to close the program.
However, I did some tests. Sending by itself is deleterious because it is intercepted wherever a sending is needed even in other programs.
I think the only solution is programmatically, when the cursor is an edit field it accepts the enter key as an save.
Or, even better, the data is saved when you leave the field.
All right!!! It was an idea but in the end it can be done without.