I’m not sure about architecture, but LibreCAD is an option.

I use a free, old version of sketch up.

I don't think you are going to get anything with the production capacity of AUTOCAD. you might be able to get FreeCAD to work for you on some DIY projects however if your looking to avoid the license fee for your business I think it's a mistake to try.

LibreCAD is a fork of FreeCAD that’s a bit more updated.