According to the web site the app Pro Camera by Moment support manual focus and focus peaking which is something you can use to keep focus in macro. What I see at the moment the app is for iOS. Also it support "shoot in Raw mode and select from HEIF, HEVC, TIFF, and JPEG" according to dpreview.
N.B. No affiliation with any of the manufacturers/...
You can use MIRO web site, it is not exactly white board you you can do it. Also Draw web site can help if you want to make diagrams.
About pure whiteboard you can add this option in Teams, but you should activate it and install specific software.