Fake true time lapse effect?

I have a video of painting. I want to be able to edit the video in camtasia to create a time lapse effect (instead of recording a true time lapse, which is just a series of thousands of photos). I feel like the video would give me more freedom to slow down and show some real time when necessary.

I found a TechSmith video on YouTube called "How to create a time lapse" but it has you just change the clip speed to 400% or so, to create a fast forward effect. But it doesn't look like time lapse - You can still see the person's hand zooming around the screen, which is very distracting and not the relaxing stop motion of a time lapse.

Does anyone have a method for creating an effect that looks more like time lapse?

I did figure out I can speed up clip speed to 5.00x then when I export the video set the frame rate to 15fps and that looks closer. But I have concerns about if I try to mix timelapse and real time elements in one video, also audio. Do I have to create one export for my timelapse, export with a low fps, then import that video into a new project?