Plex will treat them as a single Episode with 2 versions. Most clients can handle playing the versions, though I know some used to not.
As far as I know none of the clients will prompt you, it will select the highest resolution & the highest bitrate of that resolution when you click ▶ Play but you can select the hamburger menu 3 dots & select Play Version to choose the version to play, but be aware you will see the resolution & bitrate not file names to distinguish which is which. There’s a feature request for that to be better.
There IS a 3rd Party extension in development to allow you to add extras to shows, seasons, & even episodes, but I can’t vouch for how well it works unfortunately. I’ll try to find a link to it but just a warning, it’s in development, so it may stop working or have issues because it’s not a full release just yet
