Just a dumb, initial, sanity check - but have you tried getting the rotator and splitting the pins, running each component through the ClampAxis node and using that? Seems super simple and like you should have tried it, but just thought I’d ask. Probably wouldn’t work because it doesn’t actually factor the other components in (so they’d be inaccurate).
Failing that, take the rotator you wanna use but the values aren’t in your range, and see if you can’t make a quaternion from its forward & up vectors (“Make from XZ” - any of these should work) and convert it to euler (gives you a vector not a rotator).