A narrow glass panel at side of front door, it is way too bright?

Put a piece of privacy film on it

Cover with Vinyl Cling, come in many designs. or Curtain or Blind,

If you don't want to hang curtain or shade rods,, I would buy a window film (plain or patterned) and cut to fit this panel. It will not only block or reduce light, but will add architectural interest to the door - a good thing!

Yes, what John said are all alternatives or if you are artistic, paint a design with stained glass paint for interest.

I suggest that you put some painter's tape on the wood part of it and paint it the same color of your door! This will make it look like an extension of the door on the inside and might dim the brightness of the room! Hope this helps!

Denise, so glad I could help! And it is so nice to be in an on-line community where I can connect to friends way far away as Australia 😁....please let me see a finished photo so I can see what's available " in your neck of the woods"!