I think you don't need to run a full node just to transfer them to your ledger nano.
Yes, that is correct.
The only benefit of running a full node is for privacy reasons.
As you are not requesting to other nodes the balance of your addresses, nobody can link those addresses together by your requests only.
your privacy would be safer as you are requesting the balance of all addresses.
The first thing you need to do is to create a new wallet in Ledger Nano and send your coins to the addresses in your new created ledger nano wallet.
Can't you just import your BIP 39 Seed with all your 30 inputs into electrum?
As you have a mix of all 3 formats, you will need to create 3 electrm wallets, with different derivation paths, for all 3 formats:
m/44'/0'/0'/0 for P2PKH (Legacy, starting with 1)
m/49'/0'/0'/0 for P2SH (segwit starting with 3)
m/84'/0'/0'/0 for Bech32 (native segwit, bc1)