Suggestion for Admin Panel

Hello

In the admin control panel, settings section
After clicking on edit, help will be shown
But it is better to display the guide under each setting or as a floating mouse before clicking

Add change font size option in pages settings

By "guide", would you mean the setting description?

For font size, there are headers paragraph types. Are you looking to repeatedly micro adjusting normal text by just a pixel or two? You can toggle HTML source and insert any styling desired through code.

yes setting description.
not micro adjusting a button is very useful to enlarge font.
Thanks

Font size is a plugin available here. I'm not very found of adding third party components to the core. But a vMod can be written.
https://alex-d.github.io/Trumbowyg/documentation/plugins/#plugin-fontsize