I think the first of all, you need to "Backup your seeds", because:

"Not your keys, not your crypto" => you need a non custodial wallet to store your Bitcoin => you need to backup your seed phrase :) The first, and the most important!

Assuming they already have some bitcoin probably use lightning. Many people's first use of the base layer will be either to withdraw to lightning or to send to a wallet that allows them to convert to lightning.

This will give them the understanding of the base and second layer and that onchain is for saving and second layer is for spending (or micro stacking/micro spending). Eventually this might not be the case and newbies might only ever interact with secondary layers but I think current newbies should still interact with the base layer.

I voted self-custody and I guess this implies you aren't a bitcoiner if you don't have any bitcoin. Not sure how I feel about that.

In the next bull run newbies are most likely going to be starting with LN. Maybe the exchange will come first but when fees are super high they will either leave it there or withdraw via LN to a custodial wallet.

Self custody (although important) can come later as the amount they put in rises.