I have used Sketchup for years. I have occasionally felt the need to move on to a "real" CAD package; I tried FreeCAD as well as Solid Edge. The first was a bit "meh" for me, I guess it gets the job done, but it didn't scratch my itch, so to speak. Solid Edge is a professional package with a "free for private use" option, and has loads of very good tutorials online. I found it interesting as it has a parametric construction mode; i.e. you can tell two faces to stick together, or you can tell a hole and a bolt to always be the same diameter, and when you change the one of them, it also changes the other. Great if you construct something and you want to rotate/move parts around virtually to see if everything fits together. It takes some getting used to.
In the end, I always return to Sketchup. It is more oriented towards interiour architects or building planners, I think - it has no straightforward way to produce 2D plans with measurements etc. It is possible to do so, but it is a bit of an effort. The 3D stuff is totally flawless; not too overwhelming, not too many options, but very easy to quickly and intuitively model about anything I could ever hope to produce in my shop. It's just so quick to whip up a model and just get it done. Often, it is enough for me to just slap on a few measurements and print out the 3D model without going the length to produce 2D plans.