You should not have any problem with the 16" Macbook Pro with the 8GB graphics option. Definitely get 16 to 32 GB RAM and at least 1 TB SSD.
The recommendations for AC 24 are here, by the way:
https://graphisoft.com/resources-and-support/system-requirements
There's certainly no reason to even consider an eGPU until you find that you can't live without one
🙂
(I have not seen a definitive statement from Graphisoft concerning the switch to Metal. The existing code runs fine on Macs though.)
One of the forum moderators
AC 27 USA and earlier • macOS Ventura 13.6.9, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB