Default Font in Calc always Arial 10

LO 7.5.0.3 Calc always defaults to Arial 10 pt. I prefer Verdana 12, and perform a select all to set that font. Adding rows or columns reverts to Arial 10. Tried styles/manage styles/default/properties and set the new font there - no OK or Apply button. How do I change the entire sheet or file to set a default font? Tried LO preferences. I don’t use templates.

Change the file, save as a template, and mark this template as the default.

How do you restore imported .xlsx files to default template?

The default model only works for new files created in LibreOffice.
Imported files are imported as created.

At first: You can’t restore, as Excel never used a default template from LibreOffice.

Second: One should not do this, even if possible. How far do you go: My default currency is €, shall we convert $ (or £ and ¥) to Euro. How? Simply change format or currency conversion?

My default dd.mm.yyyy will not fit sheets from a normal.dot-version with yy/mm/dd as it needs more space…

I guess you stumbled over the behaviour described in the following thread. Check Villeroys description to change default cell-style or the hint of Tex2002ans to select colums and change for entige columns there:

Above link thread also links to a bug-report: 153527 – LibreOffice 7.5 Calc: unable to apply formatting to all cells in spreadsheet