In a given week I likely play more guitars than most in my work and over the last nearly 20 years I have a list of the five best sounding acoustic guitars, modern production that I have ever played. One of them is a Bourgeois with a torrified top that one of my customers asked me to inspect and bless as a keeper or not during an acceptance period. It was an incredible instrument with tone for days. Definitely a keeper!
It also had a detachable neck which is a finger in the eye to traditionalists of which I am usually thought to be and even consider myself. But I was wrong, R - O - N - G on the assertion that only a dovetail is sonically superior as many of us will find ourselves someday with the right guitar in our laps.
Here is a video with a 30,000 foot view of the justification for such an innovative neck joint and a tease look at it from afar. If it were my IP (intellectual property) I would not be overly inclined to be sharing it here or providing greater detail in a video knowing that you guys like to adopt good ideas as do I.
I can't tell and don't have direct experience taking one of these apart if they use shims or some other method to adjust the neck angle but the look I do have affords me a view of some very precise, detailed engineering that is likely one of the best neck joint implementations out here that is not a traditional dovetail.
The real reason I wanted to post this video is the excellent video's host's explanation of how important the neck angle is. He educates the audience with some important facts about the relationship between saddle height, neck angle and set-up.
I'm a set-up guy these days doing over 600 a year and I know first hand that there are drawbacks to lowering or raising saddles and that there is a optimal height for a saddle all other things functioning as they should. Most of us use 1/2" measured in the middle of the saddle between the D and G in front of the bridge from the top.
Go higher and the instrument gets louder but there is also more torque on the bridge making it rock more (hence the louder). A saddle that is too tall may:
1) Break
2) Split out the front of the bridge
3) lift the bridge
4) Encourage a crack in the middle of the lower bout and/or contribute to opening up the top's center seam
A saddle that is too short may:
1) Reduce volume to an unacceptable level
2) Reduce the break angle over the saddle in extreme cases requiring the creation of string ramps in the bridge.
3) Rattle and buzz on ski ramps, high frets or poor fret work
4) Is less tolerant of incorrectly adjusted truss rods
So this is a good video for builders, Hesh approved

and if you ever get a chance to get to know a Bourgeois guitar don't pass up the opportunity they are fantastic!
Lastly there is a notion here that the saddle height is more important than we may think and perhaps adjusting the neck angle to a fixed saddle height is a better idea than vice versa. I agree for all the reasons I provided and stated in the video.
It's also not a new concept and and I've worked on over 100 year old Hausers and others that had adjustable neck angles for these very reasons.
Today not only Bourgeois is offering this functionality in their instruments Martin is as well with the Martin SC series that is billed as even a gigging musician with a shim kit can reset their neck angle with strings on at a gig in under five minutes time. I've done it several times myself and it works well.
Enjoy!
https://youtu.be/LzYczenb7qs?si=0-THGx7ST7KgY8km