Did you transfer and type "d492948c19e7f34eddf7382a37f958bff0fdcgaedc3e556effd8b6920ff98600" manually by hand? The 'g' is rather a '9' instead.
For recovery or experiments with "naked" private keys you need a secure and expendable/wipeable environment. If you're not experienced with that, I don't want to be responsible that your keys might leak into wrong hands.
You can boot TAILS from a thumbdrive or similar (TAILS has Electrum in an older version installed and you can use that version for a wallet recovery with ease).
Be careful to cut internet connectivity when appropriate (easy with TAILS). Your recovery words should not be used/entered on a digital device that is online. Don't "massage" your private keys while online. Period!
I assume Lunu wallet used BIP-39 compatible recovery words and nothing in addition fancy that's not documented. Let's hope for the best.
Your receive address in Lunu was a native segwit address, thus I assume a standard native segwit derivation path of m/84'/0'/0'
- Boot TAILS, don't open a connection with Tor network, TAILS should stay offline for now (until later).
- Start Electrum and create new wallet, give it some name, doesn't matter, default is OK. Click Next.
- "What kind of wallet do you want to create?" --> choose "Standard wallet", click Next.
- Choose "I already have a seed", click Next.
- Click on "Options" and select "BIP39 seed", click OK to close "Options" dialog.
- Enter your 24 recovery words in the box where they belong in, with the last word it should be displayed: BIP39 (checksum: ok)
If not ok, then check for any errors. If ok, click Next.
- On screen "Script type and Derivation path" native segwit (p2wpkh) should be selected by default and at the bottom line it should read m/84h/0h/0h or m/84'/0'/0' (both are equivalent, my more current Electrum suggests m/84h/0h/0h), click Next.
[If you don't get your wallet addresses, you can repeat above steps with a new wallet file and click on the button on this screen "Detect Existing Accounts" and Electrum will try hard to find reasonable derivation paths and different account indexes while searching for addresses with transactions. For this to work you need to establish a Tor connection and internet access via Tor before you click on that detection button, otherwise it won't work to detect anything)]
- if you were offline until here, now is the time to establish a Tor connection in TAILS, you will need it for Electrum to sync your address balances.
- set a wallet password and document it on paper or leave it blank (only temporarily), click Next.
If Lunu was all standard, your wallet should now be restored in Electrum. There are some edge cases possible for this to fail, but I'm not going to discuss them unless an empty wallet emerges.
If above doesn't work and you need to import raw (hex?) private keys, they would need to be in compressed WIF format for a native segwit wallet. You can convert raw hex private keys into WIF format e.g. with offline version of bitaddress.org downloaded and verified from the Github page
https://github.com/pointbiz/bitaddress.org.
(Beware of malicious copycat sites and typo-domains of
https://bitaddress.org, the "original" is safe to my knowledge and audit.)
Go offline before you handle private keys! On page "Wallet Details" you can enter hex raw private keys and have compressed WIF representation displayed below on the right side (left is the uncompressed WIF private key representation).
E.g. the private key in hex 0000000000000000000000000000000000000000000000000000000000000001 converts to WIF KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn (compressed) -- the native segwit public address of this key has 26 transactions in the past; the uncompressed key's p2pkh address more than 1400! Some people are crazy, indeed.
You can import that private key in Electrum as
p2wpkh:KwDiBf89QgGbjEhKnhXJuH7LrciVrZi3qYjgd9M7rFU73sVHnoWn(quick steps: create new wallet, import private keys, enter with p2wpkh: prefix for native segwit addresses)
If you're unsure or don't understand a step, better ask than do something less smart.