My experience tells it's https://deezy.io/

Wait for the mempool to clear

Depends how many sats. I use Muun for small to medium size amounts. It swaps from onchain in Muun to lightning at the time you send the payment. For larger amounts I use Breez. Breez can give you an onchain receiving address and once that transaction confirms the sats are available as Lightning. The fee can run a few thousand sats though so best for larger amounts. If KYC isn’t an issue, then you could send onchain to cashapp and then withdraw back out via lightning for free.

Good question, will follow this one 👊🏼

Muun

Interested to know what options are available too. Good question 👍