Can't spot a thing wrong with your project. No freezes. This hints that it may be a resource issue - video editing is resource intensive.
What are your PC's specs: CPU/GPU/RAM/Free space on the drive?
If yours is Windows 11, 64-bit, please Install this 64-bit version of Videopad, which can utilize memory more extensively.
Confirm that the PC video driver and Direct-X are up to date... https://www.nchsoftware.com/videopad/kb/1772.html
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One way to ease the load and speed export is to experiment with this procedure, starting with a clean project (Clear Cache Files)...
1. Create the master video (no audio), making certain that the first frame exactly matches the last. In your case, the length will be 6:58.369.
2. Export that sequence.
3. Start a new project (Clear Cache Files), and ADD the sequence you just exported.
Click the Sequence tab (top-left in the bin), click the sequence and click the ADD button (under the Preview window). Do this repeatedly until the project length is what you want.
5. Add the music cuts to track 2. Just ignore the silent track 1.
To make certain that video isn't disturbed you may want to right-click to the left of the video track and LOCK TRACK.
6. UNlock video first if you want crossfades and add them at each junction. When adding crossfades, a prompt appears: choose OVERLAP (not FREEZE).
If you don't use transitions, export will be faster, but the trans will be a cut, of course.
7. Export as LOSSLESS video.