Hangs when drag-n-drop many to timeline

You left Shotcut in Automatic Video Mode. When Automatic is left, Shotcut will match the first file opened and make a video mode for that 1st file. If your file is 4k 24fps, it will make such a video mode.

In Openshot you have a project at 720p 30fps, yet you exported at 4k 24fps from that 720 video mode. Not sure how that video turned out.
2022-03-19_17-14-28

You dropped all 4 videos into Shotcut’s timeline at once.
With Openshot, you placed 1 video at a time in the timeline.