I developed a word document with vba that uses an excel file. On my pc, the .docm resides in C:\Users\....\Documents\Custom Office Templates with the Developer>Tools>References>Microsoft Excel 16.0 Object Library Checked.
(I also set the Custom Office Templates folder as a trusted site.)

When I copy the .docm to my wife's pc's C:\Users\...\Documents\Custom Office Templates the Microsoft Excel 16.0 Object Library is not checked.

I enabled the Microsoft Excel 16.0 Object library through Developer>Tools>References> on my wife's copy and Saved. Multiple times. Multiple iterations.
But every time I open the .docm on my wife's machine, the Excel 16.0 Object Library is unchecked.

And the security warning continues to appear on each open.

What I want, of course, is that the Object Library to remain checked. I'd also prefer that the security message disappears.