If you do go for NationStates, the base gameplay consists of four interactions (policy decisions) a day, although that can be configurably throttled down (or let stand, waiting to be dealt with), e.g. to exclude weekends. Hardly onerous. And you make your own aims. (I made it a point to traverse through every single Government Type, which took a while to do.)
Above that, and table-placing efforts that take no more effort, but far more time to accomplish, there are PvPish games of Raiding/Defending regions, but the effort-to-results ratio never appealed to me, and generally I kept out of those affairs.
And the internal
United Nations World Authority pseudo-player-led politicing, if you care for that, but it's not obligatory to do that, either.
Then there's an entire forum system, within which you can participate in freeform (
with agreed justifications!) roleplay of your nation, and of course entire voluble "General" discussions and forum games that have little to do with the game itself. You
could find as much entertainment there as the Bay12 lower forums. But it has also been a bit heavy on the arguments, at times. Good job
that is optional, too.
And also, around 1st April (and Halloween) the site mods tend to roll out something 'special', overlaid upon the base game. Either getbin therevquick so that you're not having to ldarn both baseline
and transient gameplays, at the same time, or wait until a week or two after whichever event has just happened so that you miss all but the after-effects of discussion about the seasonal quirks that have just happened!
IOW: It can be a low-intensity playing experience (less than you seem to want) or take over your entire online life, or anywhere in-between. Try to find your own level!