You only need to run RA3.exe as admin, hook the game to cnc online, close cnc online then run the game directly from ea app.
i have the ultimate collection from Ea app and tried all of these solutions but when i start the game from the ea app or the .exe file it self
the ea app pops up a message saying (an error on our end caused the launch to fail. Try again a little later)
BTW the game when i open the game normally from the exe RA3.exe it opens up a luncher to choose between RA3 or RA3 Up rising
Try to reinstall, that helped for me. After fresh install apply all the other steps
Idk why but doing the same proccess again seemed to have worked, i think you are not allowed to have the ea app open.
to describe my steps, fresh install of ra3(copy the the cdkey that is in the ea app for the game and close it when you have it), set the ra3.exe properties to admin (not launcher), install the patch (make sure to paste the cdkey if you get prompted for missing keys) start cnc online and hook the game and then close it, start ea app and launch the game, cnc online will appear after you select the version in the launcher, click ra3 and wait, it should launch eventually and lobbies should be visible after login.