Well it was a de jure state, it has just lost it's recognition due to the size of the PRC, however ROC does have backing of powers such as the US, just not in the same way as the US wants to trade with China, to do so means accepting the one China policy.

Kosovo was always acknowledged as part of Serbia, it only became de facto seperated because the the international community pushed Serbian forces out when they were killing the Armenian majority allowing the UN to take over.

So from a legal point of view Taiwan is better off, unless Kosovo independence is granted. But from a cultural and ethnic point of view Kosovo has the better case, even if we are not sure what to call someone from Kosovo, media just says Kosovo-Albanian and Kosovo-Serb.

Of course at a defacto stand point both are quite good. Neither follow laws of their dominating partners, both have seperate insitutions, laws, currencies and so on. Even if few recognise Taiwan while Kosovo has recognition in it's current accepted status and Taiwan has more independence on the whole than Kosovo - as it uses the Euro, UN flag, has laws from UN representates, UN military and police forces etc.
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Malo periculosam libertatem quam quietum servitium.