Hello again @mister_bludgeon!
There is a golden rule:
You should not change the format of the original material. Say, your screencast recording is a 1920 x 1080 MP4 video at 30 frames per second (fps), then this should be your export format in OpenShot. Every conversion will reduce the quality of your video.
If your source material looks fine, the editing should not make much of a difference.
If SimpleScreenRecorder works fine for you, that’s great. However, I had far better results with kazam when grabbing streaming TV (cough, cough, shame on me) whilst SimpleScreenRecorder recordings were not really crisp.
As for which screen recorder to use, there’s a comparison:
I think, you will get the best results if you record your entire screen and not a window or a section, do with 30fps and don’t change any formats in the following steps.
What I find surprising is that in your case than the youtube video was of less quality than your original. Generally speaking: Youtube has excellent import filters and they shouldn’t affect the video quality, unless you’re watching the video on youtube in a higher resolution than the source material.
You might try recording in MKV format instead of MP4. Perhaps that helps.