Just a heads up to anyone needing help with Solana transactions, i found this site to be perfect! and it has a function to export a CSV perfectly for Koinly!
I second stake.tax, used it for ATOM & SOL. Another site that does ATOM and many others (though not SOL that I can see) is Mintscan - COSMOS chain explorer by COSMOSTATION (choose a different coin at top and it takes you to eg https://binance.mintscan.io/ )
This site takes the work out of creating the csv … Magic