Funny you should ask this, as I was just thinking yesterday about how dismally I failed at this. I tried doing this myself maybe a year or so ago using some directions I found online. Unfortunately, it didn't work out so well. I used a really thick woven paper sort of material (actually, it was a woven paper window shade that I cut apart). I removed the cords from the woven wood shade, cut slits in woven paper backing where the rings were on the woven wood blind, then used Super 77 spray adhesive to spray the whole back of the window shade and adhere the woven paper backing. It worked great for a while, but over time with raising and lowering the blind, the backing worked loose and started falling down. I took the whole shade down once already and reglued it, but a couple months later, it started coming loose again. It probably would have worked better had I sewed it, but I have next-to-no sewing ability and thought the spray adhesive would work better. Live and learn, I guess. Luckily, the shades (both the woven wood and woven paper) ones were Target cheapies so I won't feel bad replacing them with something else. I'm actually looking at some woven cane paper roller shades from Country Curtains that I think will work perfectly - I just ordered swatches yesterday and am waiting for them to arrive.

Not to be a contrarian, but, I would go with curtains. Two rods; one with sheer, one with blackout curtains. Sheers could be inside mounted (wall or ceiling) and blackouts could be outside mounted (ceiling). Blackouts could then be opened all the way exposing full window. Sheers could be mounted close to window so things can be placed on sill in front of sheers. Benefits: 1. Easy to clean - shake out periodically, take down and wash once per year. 2. Open everything for that gorgeous view, close sheer for privacy and some sun blocking, close blackouts for complete sun blocking. I agree with others about covering ac unit. However I would build cabinet wall to wall and deep enough to line up with that wall section which butts out to the side of the window (assuming it's deep enough to cover ac). Real doors on each side of unit for storage (or open shelves if you want more places that have to be dusted) and vented doors/grilled doors in front of unit which can be opened for cleaning/maintenance. If top of cabinet would block air flow too much then a floor vent can be installed in the top. For a cheaper/easier solution substitute a shelf (wall to wall above ac) for the cabinet with wall mounted shelves on each side of ac and curtains hung from shelf which could be opened to expose the ac (when used) and access shelves. Preferably cabinet height matches sill height to create illusion of deeper cabinet. Curtains long enough to just brush surface of sill/cabinet.

@MrsPete My mom made a number of dresses for me when I was a kid, including the one I wore as a flower girl for her brother’s second wedding (by the time he married the 3rd and final time it was easier to buy a ready made dress :p) and when my dance costumes needed to be sewn she made those too. Those dresses and costumes are special memories for me, my mom‘s last sewing project is the quilt she made me several years ago - she only hems and mends things now. I made a duvet cover for our bed a couple years ago, pillow covers for the stationary back futon in the basement family room, and pillow covers for the sofa with chaise in the living room. The duvet I used some king sized flat sheets to make the front and back, then splurged on some pretty material and satin ribbon to ’dress‘ it up. The pillow covers for the futon I made when we still lived back in SoCal and I had access to a fabric warehouse store, what I didn’t buy in materials there I got on Etsy. The sofa + chaise pillow covers I did with cheap Walmart flat quarters in solid navy for the backs and fancier flat quarters from Etsy. The pillow forms themselves I made by ’cannibalizing’ old pillow stuffings (washed and dried in lingerie wash bags before re-use) mixed with shredded leftover fabric scraps and shredded clothing scraps, to go inside the outer covers made from an old white sheet set that was too dingy to go on the bed but since they weren’t holey they were serviceable to use for my pillow project. And yes, these projects were a lot of work. The total costs on the duvet, I spent less than I would have to buy a one of a kind duvet. With the pillow covers themselves I broke even, and the pilow forms ultimately cost me nothing since I used what I had on hand.

You can get a 3/4 inch blackout cell/ cordless in "White Knight " ( YOUR dimensions) @ Home Depot for 312.80. It will look as a pale gray when dropped down, and that is BECAUSE it is blackout. If you don't need the blackout, just privacy? You can have a clean white. If it's up all the way in broad daylight? Or partly down? And It works for you? Fine! I have used plenty of these in kids rooms. No cords, cheap enough and surprisingly decent. There are other colors.......pick an accent depending.! Just don't paint what you have lol - simply a great way to make a mess and destroy the shade, anyway. Not EVERYTHING is a DIY OPPORTUNITY https://www.homedepot.com/custom-blinds/Configurator?productId=534127