Personally I would use the Flatpak version. It’s because if Discord would go after discord clients, your account could get deleted. That scares me personally, but alas, many are braver than me. Flatpaks are great, because they are containers. That means that you choose what access discord gets.
If you find the risk, how little it might be, worth it, you could try to use Goofcord. But I would strongly advice to not use any free nitro things that comes bundled with any discord client. Because that gives discord a stronger reason to ban you.
This is my personal opinion. I am afraid of using Goofcord, but that doesn’t mean that you should be. Many people have used these clients with no problem. I hope that I have made it clear enough, by putting an ever stronger emphasis on it.