Welcome to 2024 framebuilding! 3D printing lug tolerances will be worse than CNC. However, they would be good enough to build a one-off frame. Printed lugs will also be cheaper than CNC, unless you have access to a CNC machine.
Gluing a bike together is not a bad idea at all. In fact, I think you could argue that gluing a bike together is stronger than welding a bike. Welding creates stress risers and distorts the frame.
I am very curious about 3D printing aluminum alloys. I know some are specifically designed for that application. I just never had the opportunity to experiment with it. We know titanium works well, but expect to pay $3/g (a titanium lugset would probably cost $1000).
For more inspiration, check out Kova Bike’s thread. They made a killer CNC machined lugged bonded frame:
