So did you manage to withdraw successfully? You said you want to send your money to another exchange via ERC20 or BEP20, which means you'll use wrapped tokens for that (for your BTC). Based on what I see on many exchanges, the withdrawal fees for wrapped tokens are quite similar to other native tokens of the network. I guess you're comparing the fees for native BTC compared to USDC on the ERC/BEP network? I wouldn't recommend you use wrapped Bitcoin for that though. CMIIW.