not sure where you are looking but Rasmussen polls have been showing Trump hemorrhaging support since June among his base. if you visit X this is where many of them converse, and they are quite openly unhappy with the admin lately
So he's still immune the anything that's horrendous.
The real test is how people vote. With this much confusion I think it is perfectly valid to take a few opinion polls with a grain of salt.
Much like how Dems rate their party poorly but still turn it against Trump, I'm not sure MAGA discontent with have any real impact on elections.