Stop trying to repair, uninstall, redownload, etc. It will never work.
Stop trying to contact customer service of EA. They are * and will not help you. Even if you call them in the morning, afternoon, evening, night time, they will always say their agents are unavailable and even if you reach an agent, they will make you repeat the same crap you've been doing for hours, days, weeks, (downloading, uninstalling, repairing) and after everything fails, they will say Sorry we cannot help you.
Origin was the only program that allowed people to launch their game without any problems. Now they have fixed it so that you can no longer launch Apex Legends with Origin. It will redirect you to EA to launch the game, only to repeat the same crap of "Apex Legends is already running."
So what do you do?
Download Steam, create a steam account, download Apex Legends for free on Steam and launch the game there. No problems.
Uninstall EA, delete it, disable it, remove every trace of this * program called EA from your computer.
Enjoy this problem-free launch on Steam until EA decides to force Steam users to launch Apex Legends only through EA like they did with Origin.
You're welcome