I'm talking out of my ass here, because I've never approached 450, and my swing is nothing like approaching good form. But, I have the feeling that the idea of "effortless" is not quite right. Perhaps this might be considered in retrospect, rather than what it feels like to execute. But retrospect is what guides us as we change our swings. I only say this because, at least for me, chasing what I perceive to be effortless has yet to work for me.
An example is the idea that it is commonly said that the disc will feel "heavy" when you are throwing correctly, with the proper timing. I've definitely felt this when things are syncing up and I'm getting more distance, or at least consistent distance. And I certainly could describe the overall swing execution as "effortless". Except … after the throw is all done, it feels like things happened. Work was done. Effort happened. Parts of my body definitely get tired and stressed the more throws like that I execute.
Another example, on the opposite end of the spectrum, you'll frequently hear some pros grunt as they execute max distance shots. The exact kind of grunt that happens involuntarily when you are trying to get that last little bit out of a muscle movement.
3rd example, the pro I've worked with is Phillip Bartholomew who finished 5th in distance at 2021 Worlds with a throw of 637. His description of it is that once you get to a certain point in a swing, then you can/should "throw the hell out of it".
But, you can't get there unless you feel like it is effortless.
I'm sure there are some here, people who have proven track records of giving good advice, who may think I'm constantly saying the wrong thing, perhaps find what I'm saying to be annoying. Take what I say with that caveat in mind. I just know that I have spent literally countless hours following the standard advice and it hasn't seemed to ever really come together and I've had to improve by dint of luck and grind. Perhaps (for whatever reason) I'm just on the tail end of the standard distribution of what works. An odd duck, if you will.