Does the game get any updates at all?

[Roomba Boomba]

Except the ones for Rockstar Launcher.
I know that the online considered dead by many, in comparison with GTAO, but does Rockstar update it with any content apart those 2x exp modes for a few weeks? I haven't tried it yet, I played multiplayer in RDR1 on xbox a few years ago, had a blast actually, but recently bought the prequel on pc after finishing it on xbox to try later with more than 30fps, and thought maybe to give a try to RDRO.

And, kinda off-top, but does the RDRO require much more performance like the GTAO does? I have a pc just like in the recommended specs for the game, but I know that it can't run the story mode on maxed/high with stable 60fps.

[EVIL Shenanigans]

Short answer; no. As you said, there's the monthly specials, and then there are a few things that rotate weekly like the 'Featured Series' (just various competitive missions that cycle). There used to be an 'Outlaw Pass' which they haven't done for many years. They will very rarely re-activate a previous mini-pass, like this past October they did 'Halloween Pass 2', which you can still browse it in it's deactivated state under 'Club Rewards' in-game. Otherwise, nothing new for quite a while ... they haven't even bothered patching all the bugs that you may come across regularly, unless they themselves cause it with these mini-updates.

So far as system requirements go, they should be near-identical between RDR2 and RDO.