In Calc: Where is the custom default formatting setup?

I need all cells to be always formatted by default as Vertical=middle and Horizontal=center alignment. If I select all cells and then set this formatting, it will change back each time I erase or delete cells etc and I have to do it again and again each time -a frustrating torture!
So where is the custom default formatting setup, or at least an ini file? Does it exist? If not, this is a serious omission, like omissions found in software made by amateurs.

Thanks Olivier, it works!
I think though that is should be more intuitive to find the default formatting settings. For example, inside the Format Cells window, a button “Make these settings default” could’ve made it more user-friendly.

You need to use styles.

Press F11 and the Styles and Formatting windows pops-up. Select cells styles on the leftmost button. Select “Default” and right-button click on “Default”, then Modify.

The dialog that shows-up will allow you to set the attributes needed for all cells.

If you need this setup for specific new spreadsheet, then you need to save the above settings as a template, and open that template instead of opening a New spreadsheet.

If that template is to be the default template for every new spreadsheet, then go to Templates - Organize, select your desired template, open Commands and Set as Default

This may have worked in LOv3, but not in LO4. There isn’t a Templates - Organize button.

You have to go to Templates - Manage which gives you a rather uninformative screen with tabs for the type of template (document, spreadsheet etc.). Once you’ve selected that, you get a selection of template folders which you then select to get to the templates. Then you select the relevant template and a toolbar magically appears - one of the options is “set as default”.

There has to be an easier way!

@Zen Although all format settings are always to be found and modified under Styles and Formatting , your idea is a reasonable one. Thus, why don’t you report as an enhancement request in
https://www.libreoffice.org/get-help/bug/