This is the way

Bitnob app has a custodial wallet for USD and for BTC.

The BTC wallet balance is not differentiated between on-chain or LN.

They provide conversion between local fiat (e.g., KES / Kenyan shilling) to USD or from USD to local fiat.

So a typical transaction might be to deposit using local fiat (sending from mobile money), and after conversion to USD that results in a USD balance. Then that USD balance can be used to buy bitcoin.

Deposits to the USD wallet can also be in USDT (TRC20), and withdrawals from the USD wallet balance to USDT (TRC20) are possible as well.

Deposits to BTC wallet can be on-chain, to an LN invoice, or via Lightning Address. Withdrawals from BTC wallet can be on-chain, to pay an LN invoice, or to send to a Lightning address.

USD "transfers" to pay an LN invoice are possible as well.

Now Bitnob also is the provider of Send Globally branded transactions.

So a Strike user might send USD from their Strike app, to someone in Kenya, for example, and local fiat funds would be delivered through Bitnob. But the Strike user will never know who Bitnob is. Strike is, I believe, using LN rails as the method funds are transferred from them to Bitnob -- but again, the Strike user sending using Send Globally does not touch or even know that bitcoin is in the middle of the two fiat transactions occurring automatically at each of the two ends.

Countries / Currencies: Bitnob supports today

Strike supports Send Globally through other providers (i.e., other than Bitnob) as well ...