xfconf-query --channel xsettings --property /Gtk/CursorThemeSize --set 25
Property "/Gtk/CursorThemeSize" does not exist on channel "xsettings". If a new property should be created, use the --create option.
hmm in the file… ~/.Xresources ~ links to your users home…
create the file with your preferred editor or use nano as @anon13373109 suggested already…
and it looks like you do copy pasted the config content … this is not working they are only what others are using you need to set your cursor theme name there …
something very strange happened: using firefox the cursor size is unchanged, but using QPrompt, a teleprompter app, which must be seen from a few meters and required a large cursor, the cursor size is much bigger. So my problem is solved. Just do not know why firefox cursor is small, but for me it does not matter. My problem is solved for now. many thanks to all.
I suppose the addition of that file was the reason why it worked