Does Dragon Ball Time Machine make no sense for tangential motion instead of Linear motion?

[Ripper 30]

This isn't about Timelines but movement of Time Machine since it's supposed to have a linear movement in time yet Trunks who was killed by Cell in his second trip into past doesn't go to into his actual past but the altered one where he took some solution to beat androids perhaps the detonator before being killed by Cell while going on second/third trip to his past and getting his machine stolen.

Also the Future Trunks that came into the main Timeline being able to come back to the altered timeline. So what do you think about this gripe of Time Machine moving tangentially instead of linearly?