These are two areas where good solutions may exist at reasonable price-points, but if so that information isn't widely known.
Not sure if it fits with your business model, but it would be extremely helpful for someone to carefully evaluate the effectiveness of various technologies / products / services for those areas, and provide recipes for known-good setups.
I.e., if one of your clients can tell you their current and upcoming team sizes, network connectivities, etc., you can tell them what products and services give them good video / whiteboard quality at various price points.
IME companies with remote workers tend to be "penny wise, pound foolish" regarding these things.
EDIT: To be more specific: For call quality, having good data on what setups result in good call quality in Skype vs. Slack vs. Google Hangouts etc. And for shared whiteboards, having good information on how effective / sufficient teams find various approaches such as (some website + iPads), (some website + a particular Wacom tablet), (everyone on the team having a particular model of interactive whiteboard such as this one [0]), etc.
[0] https://www.cdwg.com/product/SMART-Board-6075-75in-LED-displ...