If you just update Daedalus, you don't need to re-download the full blockchain.
I haven't tested copy pasting the data from one Daedalus installation to another, but I'd expect that this should work.
In case you wonder why it takes long to initialize the blockchain after the latest
After upgrading, you will need to wait at least 30 minutes for Daedalus to start. This is due to changes in the block storage mechanism which requires a full verification of the locally-stored copy of the Cardano blockchain.
For most updates, this should not be the necessary and you can just use the already downloaded blockchain data.