Quite a few variables here, but overall assuming EUR withdrawals to ADV wallets are free on your exchange, this should be the cheapest option, especially if you have a EUR ADV
debit card and live in a EUR country (withdrawal to a third party EUR Visa/MC credit card also an option, currently priced at 5 EUR + 3%).
USDC deposits are $1 (converted to a fiat currency of your choice, like EUR).
GBP is a less popular currency on the platform, there are no direct outside features in it, be it credit card deposits, ADV cards, or withdrawals to external credit cards. GBP would involve some conversion to USD or EUR most likely.
Hope this helps
You can just create an account for free and play with the features and exchange rates.