multiple onchain wallets, with multiple UTXOs, with various amounts.
never keep just one giant UTXO with all your BTC in it. Split it in small pieces, but not so small. Enough to be able to open regular LN channels.
make a good coin control and funds management on 3 levels, before you are moving to your cold storage. As I always said with this scheme:
https://i.postimg.cc/MTL2kvT0/3level-stash.jpg
just swap them into LN using a submarine swap service. https://darthcoin.substack.com/p/lightning-network-submarine-swaps
I always recommend to have: