How to convert PSBT transaction (base64) to raw/serialized (hex) transaction? Bitcoin Core's CLI has a converttopsbt command used to convert from raw transaction to PSBT transaction but how is it possible to convert from PSBT transaction to raw transaction using Bitcoin Core (or if not possible using another client like Electrum)?
Example of a PSBT transaction (testnet):

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
Yes, once the PSBT is finalized you can extract a fully-signed raw transaction from it (using the finalizepsbt RPC). As your PSBT does not have signatures yet, there is no point in constructing an actual transaction from it yet.