Change font size whole sheet Libra calc?

When I select “whole sheet” in Libra calc and change the font size ONLY those cells without some kind formatting (strikethrough or a different text colour)are changed.
Anything with a format or with a formula associated with them Do NOT change size?
The only way I can change the size of these cells is to individually select them (double click to enter text input) then highlighting and THEN changing the font size.
However this does NOT seem to work with any cells that contain a formula?.. cant seem to change the font size for these cells at all?
I have large amounts of date on some of my sheets and and would take an eternity to resize the font for hundreds of cells individually.
Any ideas people?
Zorin 15.3
Libra Office 6.4.6.2.

[EDIT ebot] Crying out (deleted).

Libra or Libre? Libra is MS child, but you use linux?

Update:
This only seems to happen on documents that I have converted from XLS to ODS.
Creating a new ODS document and adding new data is OK.
Copying the text from the old document to the new and the problem persists, unless I clear all formatting.

**I have spreadsheet with thousands of products listed and when sold I use the strikethrough or a text colour change to note sold etc. Some entries are in the same cell with other text.
Shame if I have to suffer the annoying different size texts in the same sheet. I do like neatness!

Please edit your original post instead of using “answer”

compo probably marked it as a solution because of the stated workaround to clear all formatting. I converted .wks to .ods and experienced the same problem and exercized the same workaround.