I don't understand...
First you ask for a pre-filter. But then you say it's not what you want.
So, you get a list filter. But now you say it's not what you want, either.
Hmmm, what do you want? You can't have your cake and eat it, too...
This is really OK, but now can I set the filter that when I load the list the date picker "from" is set automatically on today's date and the date picker "a" is set to "today + 7 days"?
I would like this to avoid to make the choose every time I open or refresh the list and to avoid to load a great number of record.
Reads like you want the list filtered for records in between "now" and "now +7 days", so it works like a pre-filter on pageload, but still have the option of resetting or changing this in the same list anytime you want?
If it weren't a date/time range incl "now", I'd say use URL filtering (where you query fields and values in the URL). Don't think that'll work in this case, though.
You may be able to achieve it with some Javascript, like pre-populating the filter fields, etc etc.
However, the simplest I can think of:
Use a pre-filter, configured to display those "in between now and +7 days" records. Eventually make that a copy of the main list, eventually (if you use both main and filtered lists often) make it two menu items. Or make the first list (= used most often) the main menu item, and the second list a "hidden" menu item but put a link to it into the intro of the first list.