I basically never liked him because his films are disgusting and make me feel bad, so I never tried to analyze his stuff too deeply. I'll admit he's a skilled film maker, but he's what I call a demoralist because he makes his audience suffer while he mocks them on a couple of levels for not having the focus & recall to see what he's really doing. This isn't every frame of his every film, I don't put Dune here, and I never watched his TV show Twin Peaks, but this is his main theme: that he hates his audience and wants to harm, humiliate, and demoralize them, and he's not alone. That's really become the norm IMO.
Eraserhead is a low budget, feel-bad film with certain audio effects meant to scar the audience's psyche. It's not just noise, it's hateful noise.
Blue Velvet is a sick & twisted mockery of normal, familial love.
In Mulholland Dr the entire coherency of the plot hinged on some mcguffin about a slipper or something (been a long time), but Lynch just threw it out the window in what seemed to me like an attempt to see what he could get away with, basically thumbing his nose at the audience.
I think there was an historical period for most Western cinema where the purpose was to demoralize and degrade the audience and its culture. Early 60's Bergman might have been the beginning, then the breaking of the Hayes code in the USA kicked off about 40 years of talented, and often--but not always--twisted people creating "demoralization cinema." In this meta-genre, Lynch is way up there.
This period ended in 2004 when Alexander Payne won the Oscar for best adapted screenplay for Sideways, which he also directed, very well I might add. It's sort of the apex of quality for a demoralizing film, one with an upbeat ending tacked onto the end in order to help the previous two hours penetrate the viewer's mind.
Since then, films are mostly just trash, like what happens when a food or drink market gets taken over by a monopoly or small cartel and production quality no longer matters because the customers' taste buds have been burnt out to the point they can't tell the difference between Classic Coke or New. That's where we are now.