I now I am probably part of a minority but I am totally lost with excel (and libreoffice calc).

I used to export to csv and use perl whenever I had to manipulate data. These days I even import to an sqlite database and use either the sqlite cli (or ruby).

Thanksfully I don't have to deal with excel files all too often.

I would contend that any user that can use Excel could pick up e.g. Google sheets instantly, especially in an audit capability where you want to scan the data (and view a couple formulae) rather than craft it from scratch.