The link below shows the document camera my office has circulated the past several years. There are 4 in our inventory but they are no longer for sale from the manufacturer. We have them set up for use with a projector or screen with a HDMI connection. But it also has a USB port that can connect directly to a computer after some software is installed. It can then be used to share content in Webex or Zoom.
https://www.elmousa.com/product/mo-1-visual-presenter/
If I were to purchase a replacement for the item above, I would get one of the following current Elmo products in this same category, but I expect them to be un-obtainable at this point in time.
https://www.elmousa.com/product/ox-1/
https://www.elmousa.com/product/mx-p2/
https://www.elmousa.com/product/mo-2/
https://www.elmousa.com/product/ma-1/
Consider a solution based around smartphones. For example, Zoom can connect and share phone screens wirelessly or with a cable.
https://support.zoom.us/hc/en-us/articles/201379235-Sharing-your-screen-iOS-with-the-Zoom-Desktop-Client
As an alternative, Webex and zoom can be run as apps on the phone. Then you just point the phone camera at what you want the remote students to see.
There are also dedicated document camera apps that can be used with your phone, such as:
https://www.ipevo.com/software/idoccam
But you can also just use the camera and software that comes with the phone to record a video or take a photo of what you are trying to demonstrate. Then distribute with email, Canvas, etc.:
https://eduk8.me/2020/03/using-your-phone-or-a-tablet-as-a-document-camera/
I intend to buy some of these for a low tech solution when they are in-stock to circulate. They are a simple solution and inexpensive for laptop users. https://store.ipevo.com/IPEVO-Mirror-Cam-6-pack–Learning-tool-for-sharing-content-on-screen_p_25.html
My office also has tripods and phone mounts to circulate, if needed.
Topic suggest by Art Ed and EDHD School of Counseling and Special Education.