Icons for the "Layers and Objects" pallet are way too tiny on my 4K (3840 x 2160) monitor.  Same for icons in the Dialog Tabs. (see attachment)  They are both OK on a 1920 x 1080 monitor, but not on the 4K.

Size adjustments with "Preferences > Interface > Toolbars > Toolbar icon size:" and "Control bar icon size:" work well, but they have no affect on the icons which I describe.

Windows 11 "Display settings > Scale" is at the recommended 150%.  If I  increase it to 250%, the Inkscape icons become more usable, but then all applications and windows become much larger than I want, so it is not a viable solution.

Similar issues with other icons, such as "Align and Distribute" have been reported in the past and were eventually fixed.  This is not the case for items described here.  Please fix!

Windows 11 Pro | Dell U2723QE monitor | Inkscape 1.4

Same, i am looking for a fix

I finally discovered a workaround that enlarges the Dialog Tab and Layer Icons on my 4K monitor in Windows 11.  The workaround does not give full control of their size, but it definitely helps.

1) Open the desktop shortcut for Inkscape (right mouse button menu).

2) Click on Properties > Compatibility Tab > Change high DPI settings > [x] Override high DPI scaling behavior.  Scaling performed by: System (enhanced).

3) Click OK. Click Apply. Click OK to close Properties Menu.

Open Inkscape and voila, larger Dialog Tab and Layer Icons!  (Note: Toolbar and Control Bar icons, described in the original post, may need to be re-adjusted within Inkscape.)