Yes solar panels and most renewables can be turned off easily if there is too much energy on the grid. The term for this is “curtailment”. Some energy sources can’t be turned off easily, like nuclear, large coal plants, and combined cycle gas turbines. So you will tend to turn off the easy things before the hard things.

The only major problem here is that this upsets the capitalists that own the generation; they don’t want to pay for stuff that isn’t producing money at every instance that it could be producing money. There are no real technical reasons why you can’t curtail wind and solar plants whenever you need to.

Worth noting that a large amount of “renewables bad” you’ll see is fossil fuel propaganda too, so be careful there.