Dear Andrew,
Thank you for your report and I am very sorry about the issue!
As I checked, this is a known issue in our defect database (please refer to it as DEF-63). The culprit here is that the program spends some seconds setting up the Renovation Filter Options menu on the UI. This issue is scheduled to be fixed in the third update of Archicad 23 and the second update of Archicad 24.
Once again, I am truly sorry for the inconvenience! In the meantime, as you have already found out, reducing renovation filters should definitely help with easing the slowness.
I hope this has answered your question! If you have any further issues, feel free to ask me again!
Thank you very much for your understanding!
Best regards,
Minh
Minh Nguyen
Technical Support Engineer
GRAPHISOFT