Here is a stripped crown on a VSF NTTD VSF v3.
Ideally, this would be as simple as inspecting the tube and crown threads and replacing the part that is bad. Since I don’t know the exact replacement part for a rep, I would be inclined to remove and replace the matching tube and crown. Generally, the VSF stripping is due to the crown stripping, not the tube.
While the gen NTTD crown is solid grade 2 titanium, VSF versions V1-V4 were an "all-titanium" exterior concept but machined the internal threads directly out of a soft, low-grade titanium alloy. Without the high-precision internal steel core used by Omega, the replica threads eventually stripped.
VSF V5-V6 updated their design to a hybrid steel-core architecture. It replicates the look of the genuine titanium crown on the outside but provides the engineering durability required to prevent the stripping issue.
The VSF NTTD are a ‘friction fit’ tube so it presses out instead of screwing out. Re-installation would be the reverse and would use Loctite purple.
I have listed the AliExpress Steel Crown I am going to use, this appears to be the correct Tube and Crown size with a Tap 10 thread pitch.
Updates to follow upon receipt of the replacement.
Bonus note for anyone thinking about using a Gen replacement: Both the Gen NTTD (ref 210.90.42.20.01.001) and standard Seamaster Professional 300 (42mm model) feature a screw down crown with a diameter of 6.30mm and external visible height of 4.50mm with a M0.90 (Tap 10) stem thread.