It was exactly as modular as the Mac mini and Mac Studio.
The only difference is that it had some PCIe slots that basically had no use since you couldn’t throw a GPU in there, and because thunderbolt 5 exists.
Yeah, sure, there were some niche PCIe things that two people probably used. Hence the discontinuation.
I am an ex-Mac user, I own a Framework. Don’t worry, you’re preaching to the choir.