That's exactly why they shouldn't use MCU/real life actors for the rides though. Guests don't care.
We've had three Spider-Man's and two Hulk's in the past 10 years... it's not a good idea to make rides around actors that are interchangeable. By the time DCA opens their Marvel land, it the Avengers ride will already be out of date if they are using the MCU versions of the characters.
Just because they are losing big names/characters doesn't mean MCU can't keep going strong. Iron Man has been mostly just a co-star at best ever since IM3 and he's the biggest name.
Black Panther, Spider-Man, Hulk, Doctor Strange, Guardians, Captain Marvel, Ant-Man, Wasp, Black Widow, etc.... I think they'll be fine. They're certainly in a better position than the DCEU (which I wish would get it's act together).