So I don't quite follow your point. If the Albanians can have the right to secede from Belgrade using internal Serb administrative borders as the yardstick to define their territory, why can't the Serbs also decide with whom they want to live and use those same administrative borders to define their territory?

Look, like I said, it makes not sense, and like I also said this taboo about redrawing borders is not a philosophical point and is causing more headaches than if people just sat down and redrew the damn borders with the agreement of the populations involved.

In my opinion you could have a referendum at the level of municipalities where each municipality chooses which side they want to be on, with some territorial transfers to ensure continuity of both territories and population exchanges. This was done in Schleswig as I mentioned, but the last time that border was touched was at the end of WWI.

As for population transfers, even when done by mutual agreement and presumably peacefully, the example of India and Pakistan shows that one would have to expect violence
Partition of India - Wikipedia, the free encyclopedia

The newly formed governments were completely unequipped to deal with migrations of such staggering magnitude, and massive violence and slaughter occurred on both sides of the border. Estimates of the number of deaths range around roughly 500,000, with low estimates at 200,000 and high estimates at 1,000,000.^[5]

But, seriously, at this point I think a bold solution like the Partition of India or the final settlement of the Schleswig question would have to be considered.

We have met the enemy, and he is us — Pogo