That said, in real-world video calls I've found that having the whiteboard be collaborative is essential. Being able to see a colleague's mouse cursor as they're asking a question out loud, or someone else being able to draw a little alternate part of the diagram right there -- this stuff can make technical planning discussions way more productive.
We started with https://miro.com, and then moved to https://beta.plectica.com for our diagrams / whiteboarding. Both are pretty great...