Very "hybrid" mishmash going on! The bannister/spindles completely at odds with home style and windows.

Since this will rarely close up, I'd re do the banister to a knee wall of 3 solid /simple 6 inch square posts, and tempered glass between, topped with a stained ledge.

Call a custom curtain shop, and have panels created to draw back completely from view below, very tailored simple linen with a black out lining. They will be seen ONLY from inside the loft space, and when pulled for privacy.

Change that 6 panel hallway door while you're at it : )

Even all glass if you feel brave

Congrats on your new home. It is beautiful. I would not change any walls. I like the view of the loft from the living area.

They have a new kind of vertical panels now that are sold at Home Depot and all blind shops and could be pulled back behind the door when not in use and could be the same color as the walls. They are inexpensive. Good luck! https://www.blinds.com/p/levolor-fabric-sliding-panel/507666?width=16&height=20&utm_medium=pla&&utm_campaign=acqsembc-g-pla-verticalsSKU+%28NEW%29levolors5076661620cNTM1o39012038&utm_source=gog&utm_term=&utm_content=&mkwid=s-dc_pcrid_289462494211_pkw__pmt__slid__product_5076661620_pgrid_59001788820_ptaid_pla-489682251340_&pgrid=59001788820&ptaid=pla-489682251340&intent=&utm_campaign=acqsembc-g-pla-verticalsSKU+%28NEW%29levolors5076661620cNTM1o39012038&utm_medium=ppc&utm_source=gog&utm_term=&utm_content=&mkwid=s-dc_pcrid_289462494211_pkw__pmt__slid__product_5076661620_pgrid_59001788820_ptaid_pla-489682251340_&pgrid=59001788820&ptaid=pla-489682251340&intent=&gclid=Cj0KCQjw7sDlBRC9ARIsAD-pDFo_xlICmWrMRbTw_okEWstXslrnMHDWoW3khxhHa-2320F3TXx-ZIYaAnKfEALw_wcB&gclsrc=aw.ds

Sorry about that link. Just click on the green!

You could remove the banister & spindles and replace with a knee wall and retractable glass panels in a style that matches the home.

I have a similar loft with office and Murphy bed.
Unfortunately, only family can use it because of lack of privacy. I researched closing it in, but
there is only one large air return in this Florida villa.

Perhaps

Room dividers give you flexibility and decorative options. Some samples from Overstock, but there are many other sources:

https://www.overstock.com/Home-Garden/Decorative-Screens/Room-Divider,/type,/6414/subcat.html?keywords=room+dividers&SearchType=Header

I would leave the opening alone. Most solutions sound expensive and as you said, most of the time it will not be needed.

Instead I would create a privacy area using wall dividing furniture. The room looks large enough. Were you going to put a bed up there? How will the room function day to day?

It would provide enough privacy for changing clothes or reading in bed.

Thank you everyone! I don’t want to close in the room because i enjoy the openness so drywall is not an option. The home is also not approved for another bedroom.
The comments on the railings are fascinating. I agree existing are more traditional aka colonial and this is a contemporary home. That will likely have to be a bigger fix down the road.
The blinds - hanging panels-idea might be the right choice!
Truly thank you all!

Emmarine9 had great idea about an open bookcase also curtains idea.I think what,s bugging peeps are the spindles jus paint then WHITE !!! & they,ll dissapear!! Go to like Walmart (any store that sells separate sheet sets )& buy a couple of king flat sheets in whatever floats yur boat & hang with those clip on rings on a rod or... buy closet rod brackets screw into ceiling then Hang a pole on it( Home Depot will sell brackets & cut pole for yu) buy some white rope to glue & wind around pole in front of brackets & for around 50 bucks yur good to go when want to open pull sheet to each side then tie to spindle with leftover rope!

Is it safe to sleep in the loft? Is there an exit other than the stairs to the main floor--how would one exit or be rescued if the stairs were in flames?

Oh brother

Function over form? Curtains of some sort seems cheapest/easiest least assault to the space but does the privacy you seek include sound or just visual? Curtains will look ODD no doubt but could give you what you need fastest with a quick pull your space is closed off and reverse when company is gone.

https://www.versare.com/

I thought this was another great idea, folds right back on itself, has wheels

Wow Houzz...you exceed expectations. A few answers...changing railings is a future project, there is a window and door out of picture in case of fire (thank you for your worry), we like the opening and prefer not to do a knee wall, and we are investigating the vertical panels someone suggested. Great compromise for our needs.
We will post a picture when it is complete! Thank you ALL!