What if you cant remember some of your smaller trades on exchanges?

So i started buying and trading crypto in the beginning of 2020. I didnt use a tax app at first and for awhile, i cannot remember all of the trades and buys and sells i made on exchanges. I have all my current holdings and recent transactions. What sort of issues would this cause me for filing my tax?

Koinly will fetch it all in for you, provided you can give it public addresses you own and exchanges you have used. Just add wallets and take it from there.