You can’t link an excel file directly unfortunately. I would love that feature though.
The easiest way is to print your excel content to a pdf and place that as a linked drawing in archicad, with auto update set. That way when you change your excel content and re-print to the pdf and save it over the top of your previous pdf, the updates will come through to archicad automatically.
Scott J. Moore | Fulton Trotter Architects | BIM Manager, Associate, Architect Since AC13 | Current versions AC23.7000 & AC26.5002 | BIMCloud Basic | Python, GDL, VBA, PHP, SQL, CSS Certified Graphisoft BIM Manger (2022) Win 10, i9-9900K, 32GB, Quadro P2200, 500GB NVMe