Take a look at Draw.io. It has an online mode, but also binary downloads for most operating systems (with everything saved locally).

I agree on your assessment of SketchUp - the old 2017 binary is still my go-to for woodworking design, even if it is a Windows install.

Keep an eye on the HDMI version - 1.4 will only give you 30fps at 4k. You need 2.0 to get 60fps.