Excel macro for bitfinex lending calculation

[Tesla71]

Hi, I am looking for some sources where I can find information regarding the following:

I want to use an excel sheet for calculation of my daily earnings from lending BTC, US$, etc on Bitfinex for tax calculations.
Bitfinex already offers a CSV Report for every day, but I need to add the specific crypto prices for each day.
The first idea was to do it with a macro, but doesn't it seem better to use an API-key to retrieve the report and the prices?

Do you think that is possible, I have some programming skills but not with web-based things and also don't know where to start.
Or maybe something like this already exists?

(please move if in the wrong forum)