Hi Paul,
Thanks for getting back to us.
The size of the ribbon icon and visibility of the rows depends on the screen scaling.
For example, here’s the screenshot of Excel 365 worksheet at 100% (recommended on my system) scaling. From the screenshot, you can see 38 rows are visible and ribbon is smaller.

Whereas in the screenshot below, only 28 rows are visible and ribbon icons are larger at 125%.

I understand, in newer version of Excel, ribbon icons are larger, and a smaller number of rows are visible. As Office applications keep updating with new features and functionality, the look also evolves. Thus, changing the size of the ribbon when compared
to Office 2010.
I know you don’t want to change the scale setting on your computer, in this regard, you can consider providing feedback in
Excel UserVoice and let the Product Group know your requirement about making the ribbon icon smaller.
UserVoice is the best way to give the feedback to Product Group as it’s actively monitored by them and many new features have been implemented from our customers feedback.
We highly appreciate your understanding.
Regards,
Neha