Yes you can buy shallow brackets, but remember they have to be deep enough so your sheers can slide.

The curtain rod shop

cant do a search with this. which ones are shallow? I need brushed nickel metal. Bracket projection can only be less then 2.5" deep.

Pick the rod type, then look for the ‘projection’ that will work for you.

Look for the orbital type brackets with what looks like a ring at the end. You just have to look thru and look for the words projection or return. They'll also tell you what rod size you need that will fit. Here's a few I found:

Orbital 2 1/2"

2 1/4"

Vesta 2 1/4"

Adjustable 1 3/4 to 2"

a bit pricey but TY

Standard projection size is 3 1/2" and double rods with 1 1/2 and 3 1/2" projections. Highly doubtful you can find a specialty size in a big box store or inexpensively for that matter.

Use a different window treatment. If these are going to "move" , nothing shallower than 3.5 will allow them to move. Even if stationary, anything less looks lousy, and smashed against the wall and window glass. That is why 3.5 is a "standard" return and bracket. A lesser return will be a more expensive rod, rings as well and may also depend on your window casing which needs a clearance.

They will be stationary and just sort of framing out the massive amount of glass.. just simple. Airy panels.

Could you have the brackets hang from the ceiling, instead of project from the wall? This solved a curtain rod problem I had.