How does a wallet decide which utxo to use? I am using a cold wallet and made a few tx two days ago. However, though what I wanted to send was a very small amount of btc, the wallet made multiple utxo of huge amounts get involved and now all my assets are locked up as the tx are unconfirmed.
Questions;

Why does a wallet have to use multiple utxo (input&gt;output 2&gt;2 or 3&gt;2) rather than just use one and split it in two (1&gt;2)? (the aimed tx amount is smaller than each utxo)
Is the algorithm to select which utxo specific to each wallet or is there any general rule throughout bitcoin network?
Why does a wallet have to use multiple utxo (input&gt;output 2&gt;2 or 3&gt;2) rather than just use one and split it in two (1&gt;2)? (the aimed tx amount is smaller than each utxo)

There's no generic reason a wallet would have to do that.

Is the algorithm to select which utxo specific to each wallet or is there any general rule throughout bitcoin network?

Specific to each wallet