There needs to be a way to comfirm the created G-code is correct.  

There needs to be a way to comfirm the created G-code is correct.

After changing a few default settings, the top 4-6mm of the project did not complete/print. Why?

There needs to be a way to visually generate/confirm a model's form from the finished G-code to know it was rendered correctly.

Firstly, a little background. I'm new at this. My Bro gave me an Ender 3 Pro near the end of October 2021. Before I even opened it, I read and watched assembly videos. I thought, "Oh this might be the ender of me." My profession is mechanical related. So the build went well. I learned right away I need a good slicer. I picked Prusa. I printed several small jobs. Not changing any of the defaults. Had some filament feed issues. I now know to watch out for that. Keep it clean and have relocated the reel for easier feed.

I got bold. There are 2 hairy lion models I wanted to print for a friend, 3 if you include the mod that has a support base for the wall on Hairy and it works. There's "Pedro" and the well known "Harry Lion". Up until yesterday, the wall for both would always fail about 1-2 cm up. A layer would  not stick to below. That nozzle looks to be moving pretty fast on that wall, I need to slow it down. I found the one with the base for the wall. I thought that model will work with some changes. I slow the job down. Make the tip a bit hotter. I dropped the X/Y speed to 80% of normal, increased the tip temp by 5 degrees. Changed the Z from 0.2 to 0.16. It was working. Here is where I think the issue is. To save time I made the size 75% of original. Maybe Prusa calculated the top layer's too thin to print and omitted them?... This also happened with another project. I'm happy.

95% of it printed. There are some quality issues with the hair filaments. Before I printed the Hairy lion, with brim on the wall version. I printed out "Benchy". It looks great. Of course it was all default settings. The lion's body looks good.

I wish Prusa had a ,, reverse import from G-code to stl or other to confirm the geometry of the G-code was created correctly.