Upvote: https://github.com/grafana/grafana/issues/18041 and add any additional comments and context there. In addition to making the light/dark themes more accessible, I think we should add an additional high contrast one.
A few things have been added that may help:
1. only visible data is queried and loaded
2. If you have multiple panels that use the same data, you can now just reuse the results (or a subset of the results) in a new panel. This will cut down on additional queries that may not be necessary