Payment with several addresses in the same wallet does not require an additional fee.
How can I understand this? If all my addresses are generated by the same seed they don't require additional fee?
transaction fee is based on transaction size and current minimum network fee rate
transaction size is calculated from the number of inputs and the number of outputs
every time you received bitcoin in any addresses, it becomes an utxo (unspent transaction output)
this utxo would be used as input for your sending transaction in the future
having multi inputs from a single address or multi addresses, doesn't make any different
but using different type of address (legacy, segwit, native segwit) will create less tx size which means less fee required