If you launch Minecraft on mcOS, the launcher is supposed to quit. It appears to, the indicator dot in the dock vanishes, but if you look in Activity Monitor you will see that the Minecraft Launcher process continues to run until the game is quit. This means that if the game crashes or you try to open the launcher while the game is running (for example to change skins) the launcher doesn't focus properly and, if there are other windows on the desktop it always moves to the back and it also does not show in the alt-tab screen. The only way to fix it is by quitting the process in Activity Monitor.

Video showcasing the problem: https://youtu.be/ebiBvLvvjqM