Is there a 'dead zone' in meditation effort?

Is there a 'dead zone' in meditation and the effort applied? So to explain 1. Going from no meditation at all to meditating even a bit (10 mins every few days) - benefits felt quickly 2. Going up to intense meditation in a retreat situation (meditating many hours a day for several days to several weeks) - benefits felt and quite long lasting 3. Meditating for an intermediate amount -(meditating 30 mins a day 5-7 days a week over months / years) - meditator plateaus and feels stuck. Little benefit felt This is just my experience but I'm wondering is it a thing - has this been pointed out in any texts or by established teachers. Or is it just me? Many Thanks