Hi,

Why not just try 3M Very High Bond double stick mounting tape from a hardware store.
You can buy it with different grades of holding power and widths.
You can sheet the whole mirror as it’s foam flexible.
It is an instant peel and stick it to it.

Automotive parts house sell it for emblems and try for an extra price for outdoor in the sun applications.
Yours would not be in the sun but then neither does it show from under emblems.
But sincerely it’s basically made one strength grade adhesive but using a wider contact surface area gives it more holding power.
If you study the selections in the hardware stores you can trim to fit as you go for other purposes.

🙄. Need a toupee anyone. Imagine a skull cap made of stick-on Velcro material.
Only problem is the style, as in, which side would you want showing?
Fuzzy or stubby😳.
YourMight try showcasing that idea in Chicago … the Windy City.
I lost my 😇 a long time ago.

😊
Phil