Online whiteboards are just awful with a mouse, what's worked really well for my livestreams has been a WACOM like tablet that I can hook up via USB to my laptop or Desktop.
I use it to annotate pdfs and also with the MS whiteboard, it's not necessarily the best to collaborate with but I really like how I can zoom infinitely out to keep adding stuff. I prefer this setup over regular whiteboards for solo brainstorming sessions
I got this, it's cheap and great https://www.amazon.com/GAOMON-M10K2018-Graphic-Pressure-Batt...
I use it to annotate pdfs and also with the MS whiteboard, it's not necessarily the best to collaborate with but I really like how I can zoom infinitely out to keep adding stuff. I prefer this setup over regular whiteboards for solo brainstorming sessions