Standard drain pipe elbows (or "bends") are available in (at least) 15, 22.5, 30, 45, 60 and 90 degree bends. You may not find all those at a "box store" but online or at a plumbing supply they can be had. 11.25 degrees is also made, I find.
With due care & caution, you can also heat PVC plumbing and bend it - but due care is required so as not to kink it, overheat it, or otherwise cause damage. Fittings are harder to screw up, and can likely get you close enough to vertical that it won't matter.
As to your assertion that "even the smallest standard fitting would not do it" that would be unlikely:
- If it's less than 5 degrees, it's within tolerance.
- If it's more than 5 degrees, and less than 6.25 degrees, you'd be
right, though there's enough slop in the fit up that you could be
wrong by applying pressure correctly when gluing.
- If it's more than 6.25 degrees, then an 11.25 degree bend will get
you within tolerance.
So you have 1.25 degrees where that could be true. If it's more than 13 degrees, you use a 15 degree bend, etc...
Or there's @Isherwood's solution if you want
perfect, rather than within tolerance.