Add the players total playtime on the server to the /whois command 👍

Good idea but probably not easily solvable.
EssentialsX would have to track all the time when a player comes online and goes offline and store these values in a database or whatever.
There are other plugins that can do that including top players of day/week/month and subtract afk time and stuff.

EssentialsX would have to track all the time when a player comes online and goes offline and store these values in a database or whatever.

Player#getStatistic(Statistic.PLAY_ONE_TICK)

This has been introduced in 7c0fa46. You can grab the feature from build 479 on the CI server.

Thank you! :)