I used to have 49" 5120x1440 display. We started with Zoom, which under Advanced would allow partial desktop sharing. I would draw a 1920x1080 box and move windows in and out of the box.
We moved to Teams and Teams only supports Window or Screen sharing. DeskPad would work great for that situation. Create a virtual display, share it and then use it on right part of the physical screen, moving windows in and out as needed.
Currently, I use 2 Studio Displays instead of the 1 Wide Screen. When I need to share screens, I press a button on Stream Deck that calls displaypacer to set the resolution on the second display to 1600x900. When done, I press the button again and it toggles the resolution back to 5K. The resolution switching is instantaneous with Apple Silicon/Studio Display making it hassle free.