"Also, my travel agent suggested a Revolut card instead of using my own credit card while in Europe."
I would make sure your travel agent has actually traveled in Europe and used this card. It seems unnecessary to me.
Meanwhile, after the issues with the power grid in Spain and Portugal earlier in the week, I'm going back to having about 50 whatevers in cash - Euro/Pounds, etc. BUT I would get them in the country after I got to my hotel. If you think this will worry you, then get 50 of each, Euro and Pounds at home from your bank. Your exchange rate will not be as good but it's such a small amount of money that it is not going to be a tragic difference.
I'll also ask if you currently use ApplePay or google pay at home? If not, I'd encourage you to set it up now, use it at home at the grocery store, pharmacy, everywhere that takes it so you get comfortable with it. For myself, this is the easiest way to pay in Europe. There are even contactless pay stations in many bathrooms now. I've used them in France and Netherlands. No lower limit on these things.