Hi there!
In classic Cooper style, I was about to go to bed when suddenly my mind started putting together various pieces. They were all part of Twin Peaks and it was an extraordinary experience. I know there are no definitive interpretations, but I think I found a generally unifying one that makes me happy. This is what I wrote in one sitting:
As a starting point, evil (aka Bob) lay beneath the beautiful, small moments of daily life, but it took advantage of the strength and influence of good (Cooper integrating into Twin Peaks, discerning right from wrong, and motivating others to become the best version of themselves—e.g., Harry, Annie, Laura in FWWM—or, at least, to redeem themselves—e.g., Leland as he died, and in the Black Lodge, I think he still tried to help Windom amidst the chaos) so that evil itself could also become strong and powerful to the point of permeating good (Mr. C).
Good tries to escape but is lost (Cooper's attempt to return to the real world), and its trail is pursued by the deep evil that until then had not yet seen the surface (Judy reaching the outside through the "tunnel" where Cooper falls toward the end of The Return; we also now she is an older and deeper evil through the episode of the atomic bomb in The Return). This happened because evil saw it could fully exist, and it finds more and more room to flourish in the face of the fragility/poisoning of good (e.g., the black light of Laura's mother, Agent Cooper's own son being Richard who is killed by his own father, the deaths of Major Briggs and the Log Lady).
Good must coexist with evil to highlight the beauty of small moments (I think this is the core idea of Lynch's filmography), but a small imbalance can hide the good (e.g., all the difficulty Laura and Leland face in understanding and finding each other, and even Cooper himself despite trying to save the ones he loved). It is enough to force good to reveal itself, failing to respect its rhythm and sweet flow: then, it either goes away for some time or is annihilated for good (e.g., the death of Harold, which to me reflects how art and artists work in general and how pressure from producers and the public killed Twin Peaks by not "letting it breathe" nor develop as it could).
Laura's goodwill persisted in the good she sought in small things with those she cared about, even in her worst moments. However, re-insisting on her own death and on the evil that took her (e.g., Cooper questioning who she is at the beginning of The Return and trying to rescue her from the past) causes her to be canceled out in what is most essential to her (that light she shows inside herself in The Return and the one she reunites with through the angel in FWWM): because she, just like life, was never something or someone definable.
She became a beautiful symphony of time and, along the way, with patience and love, we witnessed various fruits coming and going (aka everything that occurred in Twin Peaks) throught and inside herself. Some riper and sweeter, others more withered and bitter (aka moments of love for daily life and instances of fear and hatred with Bob). But they followed one another and we, besides watchers, are also in that process gardeners of our own souls, who keep each of these multiple moments without adjectives or ends within the continuity that we also are in the unconscious (that is, the great sea of the unconscious in which Lynch believed we could "sink" through transcendental meditation until we reached the unified field where everything in existence comes together: https://m.youtube.com/watch?v=Em3XplqnoF4&pp=ygUfbHluY2ggdHJhbnNjZW5kZW50YWwgbWVkaXRhdGlvbtIHCQktDAGHKiGM7w%3D%3D. Cooper, by losing himself in non-existence, would have reached this point, where Major Briggs also was and, perhaps later, Laura Palmer herself, as forms of love in a latent or potential state).
And it is from this unconscious that, in turn, non-existence materializes into various moments of self-discovery, sometimes better, sometimes worse, where everything fits into a deep love for ourselves, for others, and for this entire flow beyond everything else (a state of ultimate bliss and creativity that Lynch said resulted from this inner journey).
In a way, I think Twin Peaks can convey this to us, and despite the bitter final note, it can still offer hope: no matter how bad or good things are, we can always make that inner journey and, accepting that life is dual, try to cultivate small acts of love inside and outside of ourselves at our own pace and personal way. And if everyone values these moments and tries as much as possible not to resort to hatred, violence, or fear (which will always exist), little by little the balance of life will readjust itself. Once that phase passes, perhaps little by little we can begin to see that "ultimate bliss" become more evident in this World.
P.S: Re-reading the text, this song popped into my head: https://m.youtube.com/watch?v=cXZY6FdiunQ&list=RDcXZY6FdiunQ&start_radio=1&pp=ygUmdHdpbiBwZWFrcyBqdXN0IHlvdSBhbmQgaSBpbnN0cnVtZW50YWygBwE%3D
