The angular momentum holds up the protoplanetary disk from falling into the protostar. Every little bit of it is in orbit around the protostar.
And there is virtually always angular momentum since there is virtually always sideways motion in space which is what gives rise to angular momentum. A nearly straight-in radial collapse to a protostar is very rare.
Other kinds of accretion disks (e.g., black hole accretion disks and planetary rings), probably also tend to be aligned by the axisymmetric gravitational field of the central object which arises for the same reason as for protostars. The relaxation process acts too, of course.
In fact, yours truly believes that planetary rings are mostly aligned with the planet equatorial plane of the planet by the planet's axisymmetric gravitational field. However, yours truly CANNOT find a reference that spits out this factoid. As aforesaid, the relaxation process acts too, of course.
Note that in the case of planetary rings, the tidal force of the planet prevents the planetary ring from coalescing under self-gravity into a moon.
For an example of equatorial plane planetary rings, see the rings of Saturn in file saturn_rings_orientation_perspective.html.
This is certainly partially due to the PARTIAL conservation of angular momentum as the distribution of the rotating material becomes more compacted. It can't be completely conserved in protoplanetary disks.
Angular momentum depends on mass distribution and rotation frequency (cycles per unit time). If no outside forces act, angular momentum is conserved.
In particular, if the mass distribution of a system becomes more compacted due to internal forces, then frequency must increase to compensate and conserve angular momentum.
Now for a ---if yours truly can find the equipment---Yes/No.
The old rotating platform and hand masses demonstration is good here. Call for a student volunteer---one who does NOT know the meaning of word fear.
But the figure skater video OpenStax: Angular Momentum V2: Physics Concept Trailer: Figure skater spins | 1:15 is better anyway. See Sport videos below (local link / general link: sport_videos.html):