Performance: Performance getting worse and worse as long as you have more and more elements. Same with loading time. Some cache preload would be awesome..

Anchors: See example https://clickup.canny.io/feature-requests/p/mindmap-need-layout-fix mostly related to MindMap.

Connectors: The connecting arrows are not always straight, although the elements between which the connection occurs are ideally one after the other with the same width and height data.

Please check eraser.io how their whiteboard is working with arrows and performance, and compare with current your whiteboard.