I’m sorry for your losses.
How long ago did you add the new fish? Was it just in the last few days? Ich just does not kill that fast. There is something else going on and it is most likely a water quality issue or possibly some kind of toxin introduced into the tank. Taking pictures of the dead fish can sometimes help us decide what happened. It doesn’t always work, but sometimes there will be something that gives us the clue needed to help you with the next steps.
if you don’t have the fish to take pictures, then you’re pretty much going to be stuck with starting completely over, disinfecting the tank, getting all new substrate, new filter media after disinfecting your filter, and either disinfecting or replacing all your tank contents.
if you disinfect with bleach you should rinse everything very thoroughly at least 3 times or more. I usually rinse 5-6 times after bleaching, particularly on more porous materials. Then start completely over with cycling the tank and be sure to use the high end dose of a good dechlorinator after any bleaching.