Looking for simple answers to some simple questions

Hi all and straight of the bat sorry if these questions have been answered before.

I am looking for some answers in simplest format or as close to yes or no as possible. I have looked in FAQ and have already answered some but these are what i have left.

we are travelling to Florida for annual holiday and i got the card purely to use in restaurants to pay for food nothing else no ATM, no fuel and no shopping. I usually take all cash as i don’t like how you loose sight of your card when paying the bills and feel very uncomfortable with the tip sytstem when using a credit card. I suppose i am a very un-trusting person but writing something on a piece of paper and hoping some ones does not change it seems very strange.

so here goes :-
1: can you pay the bill with revolut select no tip but then just pay this in cash?

2: i intend to keep the currency in GBP will they just do the conversion on the fly?

3: would it be easier to change it to USD (i understand regards not being able to guarantee rate)

4: what is dcc and will this effect me if i am only using this in a restaurant?

5: if i change my money to USD will this negate any need to worry about extra/hidden charges ?

sorry for the long message especially as asking for short simple answers.