Rough idle

Misfires can be caused by many things.
Bad spark plug, bad coil, bad fuel injector, burnt valve (intake or exhaust) bad head gasket, bad camshaft (lobe worn down) or faulty control to the cylinder.

You tried a plug and coil. Get a compression tester and see if that cylinder has the same pressure as the rest.
https://www.2carpros.com/articles/how-to-test-engine-compression

If it is the same then you can try moving the injector to a different cylinder. If the misfire follows the injector you found the problem. I would also try moving the plug.

When you remove the plugs to do the compression test, compare the one from #1 to the others. If it is very clean or markedly different it should be obvious.