The miners fee actually gets included in the coinbase tx of each block! For a normal tx you can calculate the fee by subtracting the sum of the outputs from the sum of the inputs. It’s pretty cool that the fee is implicit rather than an explicit utxo. It saves a lot of space on the chain
Discussion
You never stop learning… This means that you are absolutely right and Sparrow’s 150 vB is correct. 277 - 124 = 153 vB. Case closed. Thank you very much 💜