I did something similar recently, old house, wanted floor plans for renovation / idea generation.
Initially I started with FreeCAD and used the BIM functionaly, worked well, but a few bugs at time.
I've done a few smaller scale models of some rooms recently in [Bonsai](https://bonsaibim.org/(formerly BlenderBIM), and found the process a little more pleasent. This could be due to my previous blender experience and the hotkeys being more on my bones.
I think you'd be surprised, the on ramp I would say is easier than FreeCAD.