I keep up to date with everything I'm reading, most of the stories I've read are finished already with the odd one that hasn't been updated in years. Then I have all my current reads which are mostly newly releasing stuff and then older stuff that's currently on hiatus. My notifications don't blow up as often as you might think since everything updates at different times/days. plus mgo only sends you notifs to the bell twice a day so I get notified the same as everyone else does just, I usually get around 10-20 stories in my update list at a time.
I don't find it hard to keep up with stories or their plots tbh, idk how it is for others but for me I tend to go back and re-read plots I enjoy. With ongoing stories since they're newly releasing it's easy to remember the general plot since it probably hasn't been very long since I read the last chapter, so far I've never forgotten the plot of anything I've currently been reading, for older stories I tend to just re-read them anyway. I think I've dropped around 60 stories in my "Already read" just cuz I either didn't like the plot, thought the story was boring or something a character did made me lose interest.

sometimes I wonder how can people read more than 1000 manhwa.. I’ve been here since 2021 and I read manhwa almost everyday and yet I just reached 300th manhwa