I was facing the same issue with very poor performance and narrowed the issue down to the XAxis. After implementing windowing for displaying data to reduce the amount being drawn in the chart, I also applied the same technique to AxisMarks to get acceptable performance.
I basically observe the scroll position and provide the data and marks in an area around that position, while keeping chartXScale and chartXVisibleDomain constant.
Topic:
UI Frameworks
SubTopic:
SwiftUI
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