Current BTC withrawal fee on an exchange (Kraken)

The current minimal withrawal fee for BTC is listed as 0,0004 BTC (about 24 USD (massive))

The current average transaction price I found is 7 USD, but 4 USD seems to be frequent with lower priority. (52 sat/vB from mempool)

My question is: Am I missing something? Am I calculating transaction size in vB right by assuming simple transaction from cold storage to an exchange is 1 input / 1 output?