Your money is NOT protected with revolut. They are required to ringfence the client money, but if a rogue employee runs off with it and revolut go bust, you are SOL - there will be no government dept stepping in to refund you.
With Monzo, you are protected up to the FSCS limit (85k at the moment, but it varies as it is currently set by the EU at 100k euros or equivalent). Whatever goes wrong with Monzo, you will get your money back up to that limit.