I think that works only if you start the selection at the beginning of the flow, or catch a timesig/keysig at the beginning of the selection.
Otherwise the paste will be in the wrong key, or be missing bar lines.
But, yes it is important to use the system track. I assumed the OP tried that… [“not too much work with the super awesome system track”]
shr23, I also read the OP, and it clearly says “none of the meter changes come”. If they’d used the System Track to select before copying, then granted, the initial meter may not have been copied, but all other meter changes would have copied.
One could always add a meter indication to the first measure of the intended section, use the system track to copy and move the segment, and then remove the added meter from the original file.