Ability to show column-specific tooltips when mousing over a table on a dashboard

Some dashboards end up with large tables with lots of columns shown. It is normal that some of these columns may need a few notes to help a user understand its purpose / intended interactions etc.

Currently I use an instructional text box at the top, but this can be very long, hard to read, and frankly overwhelming amount of text.

I'd like to be able to add column-specific instructions so when a user mouses over a column they see a tooltip with only the instruction I set. This would improve user experience for end users by having instructions show up when & where a user needs them and disappear when they no longer do.