(Edited, that solution is easy on Plant3D 2023, I tried on 2022 and the interface is poorer)
Try on project setup, isometric DWG settings, dimensions
What to dimension itens.
You also can changes the Themes options: default, continuation. existing, fitting and smal bore options.
![joaslima_1-1677583980224.png joaslima_1-1677583980224.png](https://forums.autodesk.com/t5/image/serverpage/image-id/1182444iF7E63DCEA00709B3/image-size/medium?v=v2&px=400)