I’m my US based bitcoin experience, There are a few options. You could use Strike if you have time to wait, But Crypto.com is the fastest exchange. The fees are sometimes high because of trading volume, But reasonable. Coinbase, River, Swan, Strike, All have one week minimum waiting periods for bitcoin/fiat to settle. You can buy and send to cold storage in as fast as you can use the app on Crypto.com. It sucks to use the exchange but it sucks to suck. Probably mining is the only other option.