How much can you do on a tablet? I would recommend no less than 8 GB of RAM. If the mouse is bogging down, then it is probably indicating a slow computer, tablet, or whatever. I was having problems with Ubuntu and Windows. Many people run into mice problems like that. That is why I use Ubuntu Mate instead of Ubuntu.

Autocad

Here is a thread that talked about Autocad. Somebody mentioned a few alternative programs to Autocad for Ubuntu.

AutoCAD on Linux

This other article talked about using a virtual box in order to run AutoCAD.

Windows

I don't mind using Windows sometimes. And, of course, you can continue using Windows when you need to or whenever you want to. On top of that, like I said before, some programs either might not run on Ubuntu or it might very tricky to get it to work. I was just trying to say that it might be possible. I have not run a virtual box. I have done some dual booting. I almost got a virtual box working a few times years ago or something like that. I may give that another try someday. Wine has helped me a few times in the past. But virtual boxes may require like 4 GB of RAM or something that is rather big. So, in other words, you would need a lot of RAM, probably. Maybe not a tablet or a phone.

Using Windows

As long as you are not too dependent on Windows, I think it is fine. If you ever needed to run a Windows program on Ubuntu, it could be good to know how to do that because it is all about having the freedom to choose. Otherwise, you can begin to feel trapped into only using Windows. That's one of the reasons why I'm writing this. Just want to make sure you know that there might be some choices that you can sometimes make if you want.