For 2,500 USD you currently get the most USDC on Revolut X: 2,497.00 USDC. The least favourable exchange (Binance) gives you the equivalent of 87.78 USD (3.51%) less.
Exchanges with a direct USDC/USD market: Revolut X, Kraken, Bitstamp, Binance. Elsewhere you need a currency conversion or an intermediate currency, which usually adds cost.
Counting only the trading fee and slippage, Bitstamp wins, but once deposit, conversion and withdrawal are included, Revolut X comes out cheapest.
Revolut X leads both for 250 USD and for 25,000 USD, so it also has the deepest market for this pair.
Even for 25,000 USD, splitting the order across exchanges brings no benefit, so one exchange is enough.
USD deposits: Card (Binance, Coinbase); SWIFT (Kraken, Bitstamp); ACH (Coinbase, Crypto.com); P2P (Kanga Global); Revolut account (Revolut X).