We're open plan too and I'm considering getting one of these, might stop the dog causing chaos in the kitchen too! YOOFOR Retractable Gate for Babies and Pets (140 cm Wide), Extra Wide Safety Baby Gate 83 cm Tall, One Handed Silent Operation. Mesh Safety Gate for Stairs/Outdoor/Doorways/Hallways, White https://amzn.eu/d/4fDUKcG
We have an open plan and have a retractable gate like the one above! :)
https://www.argos.co.uk/product/4599469?istCompanyId=a74d8886-5df9-4baa-b776-166b3bf9111c&istFeedId=c290d9a9-b5d6-423c-841d-2a559621874c&istItemId=ixilqqrmi&istBid=t&&cmpid=GS001&_$ja=tsid:59157%7Cacid:278-707-7346%7Ccid:20213315256%7Cagid:%7Ctid:%7Ccrid:%7Cnw:x%7Crnd:11943702828576140399%7Cdvc:m%7Cadp:%7Cmt:%7Cloc:1006886&utm_source=Google&utm_medium=cpc&utm_campaign=20213315256&utm_term=4599469&utm_content=shopping&utm_custom1=&utm_custom2=278-707-7346&gad_source=1&gbraid=0AAAAAD9II9mAcpKhsg36tYF1R7UCz_nqT&gclid=EAIaIQobChMIkZvgy9PKhgMVZppQBh1yeyoJEAQYCSABEgKAV_D_BwE&gclsrc=aw.ds We have something similar to this, it can be a play pen, but also opens up to be a room divider
Have you thought about a play pen? I've seen some that you can buy extra panels, you could add to fit the area you want blocked off, or even a dog one, could be cheaper.