Thanks for the details. My question regarding this was more about "if I just need to dumpwallet from console in Bitcoin Core, then do I really need Bitcoin core to start syncing?"

I think dumpwallet command should work even if the Bitcoin core client is not entirely synced up

One more question I have which I would really appreciate if you can clarify. Most articles online talk about using dumpprivkey command for a specific address and importing that into Electrum

I instead want to dump the entire wallet to a file and then import the whole wallet into Electrum. Is that possible to do for all at once?