I just looked at my local exchange rate then calculate the amount arrived on that platform and withdraw them directly to my bank. I can withdraw that money on the same bank so that I won't pay any fee. It is not that complicated actually. We just need to get the amount where we can exchange it to a fiat currency after the deduction of all the fees needed. I don't know why it is that complicated as you are talking OP.
Just collect everything on an excel spreadsheet or get an app. Nothing will ever be 100% accurate but some can come pretty close and you can choose the exchange you'd like to use for your data.
Please read the opening post. It's obvious that an estimated value will never be 100% accurate. I'm only asking if anyone has any ideas on how to make the figure more accurate.
Is one exchange better than the next?
Is there a website that averages values from many exchanges?
Just any ideas that might help to gain some degree of accuracy.
I agree we should deduct all the expenses and charges.