Currently BECH32 adresses are not supported by the API, and even though you can send bitcoins to such an address manually from blockchain.com, but you can't do it from the API.
When sending bitcoins using the API, sometimes the bitcoins are sent from multiple addresses in your wallet making the transaction have multiple inputs and thus requiring you to spend more fees, and even when you choose the $from parameter, sometimes it does the same thing and sends the bitcoins from the same address that you chose but it inserts it multiple times in the input section.
This post includes two issues: