Archive node can go as low as ~2TB depending on the client, but regardless you do want to compare it to a full node, as the only difference is an "archive" node

Archive node can go as low as ~2TB depending on the client, but regardless you do want to compare it to a full node, as the only difference is an "archive" node keeps the state at any block (e.g you want to replay a transaction that occured in the past, or see a state at a certain block). The full nodes still contain all events/txs (DEXes will emit events, akin to logs, for transfers) - so it's fair to compare it to a full node. On CEXes you see a lot more trades, market makers/high frequency trades just doing a ton of volume/creating orders and so on, since it's a lot cheaper. CEXes without a doubt have more trades than DEX by orders of magnitude. Additionally, they probably log multiple stuff for every request, including API request, which they most definitely get a ton of.