If you are looking for FOSS CAD, then FreeCAD 1.0 is about the only game in town. SolveSpace is fine for fairly simple uses but lacks all the advanced toys one might like. Nor has it been updated in 3 years now. Siemans SolidEdge has a free community edition, but it’s Widows only. OnShape is is a popular alternative to Fusion, and is fully cloud based, but it is restricted like Fusion.
As an acolyte that wears the sackcloth and ashes of FreeCAD, there is a growing community of tutorials, (I highly recommend MangoJelly on youtube) for beginners to learn with. But the learning curve can be steep as you get past the basics. There is a FreeCAD community here, but it’s small and not very active. Sadly the best place for answers remains on reddit.
Yeah, those are going to last at -40F/-40C nights we often experience where I live. Nor do I see them being able to add any cool relief from their shade on a hot day.
That said, it is hard to grow healthy trees in the poisoned soils of a big city. They tend to struggle and be sickly when choked by concrete and asphalt.