Hello JimHicks200282,
I worked with "old" macbook pro 2015 with Catalina with AC24 without any slow loadings.
Now I work with the same computer with BigSur always without slow loadings.
My configuration :
MacBook Pro (Retina 13 pouces, début 2015)
MacOS 11.2.3 (20D91)
2,9 GHz Intel Core i5 double cœur
16 Go 1867 MHz DDR3
Intel Iris Graphics 6100 1536 Mo
What about yours and what about your Archicad 24 version ?
Archicad 24 3022
Archicad 24 4007
Archicad 24 4018
Archicad 24 5000
Archicad 24 5004