3D printing deisign applications that actually work?

[Cougar281]

I've got a 3d printer coming, and while I have a bunch of STL files for items that are of use, but I'd also like to learn to actually make things I need from scratch. That's where design software comes in and is my issue.

I've tried three out of the top five in this list, and in my opinion, they all suck. The simplest of things like moving around the item essentially don't exist in any of them. In Cura, for example, you hold your right mouse button and drag around, and you move about your object. In every other application I tried, there is no 'easy' way to just rotate around your object. While there are some out there that would claim that I'm the smartest person they know, and while in some regards that may be true, you'll never hear me claiming to be the sharpest tool in the shed. I suppose it's possible that I'm crazy smart in some areas, but certainly not all - no one knows everything.

For my first 'adventure', I'm trying to make a very simple piece. 20mm x 12mm x 205mm, with a 7mm hole at one end centered at 12.5mm from the end and a 7mm hole/slot at the other end centered at 11.5mm from the end (12.5mm would work too). Pretty simple to make, you'd think. Not so much.

I was going to post a picture of what I am trying to replicate, but for the first time ever, apparently, the site won't let me upload pics directly or even link to my cheverto server. *shrug*.

In Blender, I couldn't even figure out how to get the stupid thing to the dimensions I needed, let alone anything further. I mean, I saw the object, but nowhere could I find any idea what it's dimensions were - it could have been 20mm x .2mm x .02mm for all I know. In 'Fusion 360', I was actually able to set a scale and make my object to the dimensions I needed, I was also able to make the proper hole at one end, as well as radius the edges to smooth them out - but when it came to trying to make the slot at the end that needed the slot - a total fail (I was able to make a hole at each end, but when it came to making it a slot total fail). You'd think it woudln't be that hard even for a total noob.

First, I don't want something 'web based'. I want something installed on my machine that I don't need to use some sucky browser to use (let's be honest - ALL browsers suck these days). I don't want some subscription (read: ransom) based application - if I'm going to pay for it (which I'm not against paying for something that's QUALITY - but I will NOT pay a perpetual ransom for the 'privilege' of using some software), I want to pay for it and be able to use it forever (within the confines of the version I purchased and such), not keep paying for the 'pleasure' of using the program.

So within those parameters, can anyone suggest an application for designing 3d objects that is actually EASY to use for someone that hasn't been using similar software for a decade plus? All of the applications in the list I posted may be considered good for those familiar with similar software for decades, but nothing that I've tried seems at all 'noob' friendly.